DOCSLIB.ORG

Development of DLC-Coated Solid Sialon/Tin Ceramic End Mills for Nickel Alloy Machining: Problems and Prospects

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Development of DLC-Coated Solid Sialon/Tin Ceramic End Mills for Nickel Alloy Machining: Problems and Prospects coatings Article Development of DLC-Coated Solid SiAlON/TiN Ceramic End Mills for Nickel Alloy Machining: Problems and Prospects Sergey N. Grigoriev , Marina A. Volosova *, Sergey V. Fedorov, Anna A. Okunkova , Petr M. Pivkin , Pavel Y. Peretyagin and Artem Ershov Department of High-Efficiency Processing Technologies, Moscow State University of Technology “STANKIN”, Vadkovskiy per. 3A, 127055 Moscow, Russia; [email protected] (S.N.G.); [email protected] (S.V.F.); [email protected] (A.A.O.); [email protected] (P.M.P.); [email protected] (P.Y.P.); [email protected] (A.E.) * Correspondence: [email protected]; Tel.: +7-916-308-49-00 Abstract: The study is devoted to the development and testing of technological principles for the manufacture of solid end mills from ceramics based on a powder composition of α-SiAlON, β-SiAlON, and TiN additives, including spark plasma sintering powder composition, diamond sharpening of sintered ceramic blanks for shaping the cutting part of mills and deposition of anti- friction Si-containing diamond-like carbon (DLC) coatings in the final stage. A rational relationship between the components of the powder composition at spark plasma sintering was established. The influence of optimum temperature, which is the most critical sintering parameter, on ceramic samples’ basic physical and mechanical properties was investigated. DLC coatings’ role in changing the surface properties of ceramics based on SiAlON, such as microrelief, friction coefficient, et cetera, was studied. A comparative analysis of the efficiency of two tool options, such as developed samples of experimental mills made of SiAlON/TiN and commercial samples ceramic mills based on SiAlON, Citation: Grigoriev, S.N.; Volosova, doped with stabilizing additives containing Yb when processing nickel alloys (NiCr20TiAl alloy was M.A.; Fedorov, S.V.; Okunkova, A.A.; used as an example). DLC coatings’ contribution to the quantitative indicators of the durability of Pivkin, P.M.; Peretyagin, P.Y.; Ershov, ceramic mills and the surface quality of machined products made of nickel alloy is shown. A. Development of DLC-Coated Solid SiAlON/TiN Ceramic End Mills for Keywords: diamond-like carbon coating; high-speed milling; nickel alloy; SiAlON; spark plasma Nickel Alloy Machining: Problems sintering; roughness; wear resistance and Prospects. Coatings 2021, 11, 532. https://doi.org/10.3390/ coatings11050532 1. Introduction Received: 13 April 2021 At present, heat-resistant nickel alloys such as Inconel 718 type are widely used to Accepted: 28 April 2021 Published: 29 April 2021 manufacture critical parts operating under high thermal loads. For example, it can be noz- zles and working turbine blades, fairings, et cetera. The high-performance characteristics Publisher’s Note: MDPI stays neutral of parts made of nickel alloys determine the difficulties in their machining, accompanied with regard to jurisdictional claims in by increased heat and power loads on the cutting tool [1–3]. The machinability factor for published maps and institutional affil- high-temperature nickel alloys is in the order of 0.25 compared to the machining of C45 iations. steel (according to EN 10083-2: 2006). Simultaneously, solid carbide end mills are the most popular and versatile tool for machining aircraft parts. A modern approach to solving the problem of increasing machining nickel alloys’ productivity over the past years is the development and use for these purposes of end mills made of tool ceramics [4–6]. Today, large international companies, which are recognized leaders in cutting tools production Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. (Kennametal, Mitsubishi Materials, Iscar, and others), produce solid ceramic end mills on This article is an open access article an industrial scale [7–9]. Figure1a shows an example of industrial use of solid ceramic end distributed under the terms and mills made of SiAlON material for high-speed milling a turbine blade made of nickel alloy conditions of the Creative Commons on a multi-axis computer numerical control (CNC) machine. Attribution (CC BY) license (https:// The main advantage of using ceramic end mills when machining nickel alloys over creativecommons.org/licenses/by/ carbide tools is higher heat resistance. Nickel alloys of the Inconel type begin to soften ◦ 4.0/). at cutting temperatures of 800 C and above (Figure1b), after which significantly lower Coatings 2021, 11, 532. https://doi.org/10.3390/coatings11050532 https://www.mdpi.com/journal/coatings Coatings 2021, 11, 532 2 of 27 power loads accompany their machining on the tool [1]. These temperatures correspond to cutting speeds above 350 m/min. Tool ceramics can be successfully operated due to their higher heat resistance in this high-speed milling mode. Sintered hard alloys at cutting temperatures over 800 ◦C lose their hardness rapidly (Figure1b), which excludes Coatings 2021, 11, 532 the possibility of their use in high-speed milling nickel alloys using the surface2 of layer28 plasticization effect [10,11]. (a) (b) FigureFigure 1. An 1. An example example of of industrial industrial use use of of SiAlON SiAlON solid solid ceramicceramic millsmills in high-speed milling milling of of a anickel nickel alloy alloy turbine turbine blade blade (a) and(a) and the the variation variation in in surface surface hardness hardness of of end end mills mills producedproduced from ceramics and and hard hard alloy alloy (b ()b )as as a afunction function of ofthe the cutting temperature. cutting temperature. PracticeThe main shows advantage that among of using a wide ceramic variety end mills of well-known when machining technical nickel ceramics alloys brandsover carbide tools is higher heat resistance. Nickel alloys of the Inconel type begin to soften at for tool purposes for the solid ceramic end mills manufacturing, the most suitable ceramic cutting temperatures of 800 °C and above (Figure 1b), after which significantly lower material is SiAlON (silicon-aluminum oxynitride), which belongs to the class of ceramics power loads accompany their machining on the tool [1]. These temperatures correspond based on silicon nitrides [12–15]. This ceramic consists of three or more phases: α-sialonic, to cutting speeds above 350 m/min. Tool ceramics can be successfully operated due to β-sialonic, and amorphous or partially crystallized grain-boundary phases. Sintered their higher heat resistance in this high-speed milling mode. Sintered hard alloys at cut- ceramics based on α/β-sialons are characterized by a unique combination of even higher ting temperatures over 800 °С lose their hardness rapidly (Figure 1b), which excludes the hardness than traditional silicon nitride while providing a high level of strength properties. possibility of their use in high-speed milling nickel alloys using the surface layer plastici- α β Thezation-sialon effect phase [10,11]. has a high hardness that is retained at elevated temperatures, and the - α β sialonPractice phase has shows a high that impact among strength a wide and variety fracture of well-known toughness. technical- and -sialonsceramics are brands ideally combined,for tool purposes and the for ratio the betweensolid ceramic these end phases mills canmanufacturing, be quite easily the variedmost suitable when preparingceramic powdermaterial compositions is SiAlON (silicon-aluminum (raw materials or oxynitride), precursors) which for subsequent belongs to sintering the class[ 4of– 6ceramics]. It makes itbased possible on silicon to obtain nitrides a different [12–15]. set This of ce physicalramic consists and mechanical of three or propertiesmore phases: of α the-sialonic, sintered ceramicβ-sialonic, necessary and amorphous for the cutting or partially tool’s specificcrystallized operating grain-boundary conditions phases. [16–19 Sintered]. ce- ramicsMoreover, based on any α/ ceramics,β-sialons are even characterized those obtained by a usingunique the combination most advanced of even technology, higher arehardness structurally than traditional inhomogeneous silicon nitride materials while that providing a priori a contain high level certain of strength defects proper- (such as micropores).ties. The α-sialon The sinteringphase hasprocess a high hardness of ceramic that powders is retained involves at elevated providing temperatures, an increased and temperaturethe β-sialon modephase has and a ishigh very impact technologically strength and complex. fracture toughness. In sintering, α- and grain β-sialons growth are can occur;ideally a significantcombined, and amount the ratio of residual between glassy these phasephases can can be be formed, quite easily which varied worsens when the hardnesspreparing and powder strength compositions of the material (raw during material high-temperatures or precursors) operation for subsequent [20,21 ].sintering Excessive porosity[4–6]. Itcan makes form it possible at a low to rate obtain of grain-boundary a different set of diffusion physical andand insufficientmechanical shrinkageproperties of theof powderthe sintered composition, ceramic necessary which sharplyfor the cutti worsensng tool’s the specific sintered operating ceramics’ conditions fracture [16– tough- ness19]. [22–24]. It should be borne in mind that a sintered ceramic workpiece, to obtain multi-edgeMoreover, tools, any must ceramics, be subjected even those to dimensional obtained using shaping the most processing advanced by technology, mechanical methods.are structurally One of inhomogeneous the
Load more

Recommended publications
  • The History Group's Silver Jubilee
    History of Meteorology and Physical Oceanography Special Interest Group Newsletter 1, 2010 ANNUAL REPORT CONTENTS We asked in the last two newsletters if you Annual Report ........................................... 1 thought the History Group should hold an Committee members ................................ 2 Annual General Meeting. There is nothing in Mrs Jean Ludlam ...................................... 2 the By-Law s or Standing Orders of the Royal Meteorological Society that requires the The 2010 Summer Meeting ..................... 3 Group to hold one, nor does Charity Law Report of meeting on 18 November .......... 4 require one. Which papers have been cited? .............. 10 Don’t try this at home! ............................. 10 Only one person responded, and that was in More Richard Gregory reminiscences ..... 11 passing during a telephone conversation about something else. He was in favour of Storm warnings for seafarers: Part 2 ....... 13 holding an AGM but only slightly so. He Swedish storm warnings ......................... 17 expressed the view that an AGM provides an Rikitea meteorological station ................. 19 opportunity to put forward ideas for the More on the D-Day forecast .................... 20 Group’s committee to consider. Recent publications ................................ 21 As there has been so little response, the Did you know? ........................................ 22 Group’s committee has decided that there will Date for your diary .................................. 23 not be an AGM this year. Historic picture ........................................ 23 2009 members of the Group ................... 24 CHAIRMAN’S REVIEW OF 2009 by Malcolm Walker year. Sadly, however, two people who have supported the Group for many years died during I begin as I did last year. Without an enthusiastic 2009. David Limbert passed away on 3 M a y, and conscientious committee, there would be no and Jean Ludlam died in October (see page 2).
    [Show full text]
  • A 1 Case-PR/ }*Rciofft.;Is Report
    .A 1 case-PR/ }*rciofft.;is Report (a) This eruption site on Mauna Loa Volcano was the main source of the voluminous lavas that flowed two- thirds of the distance to the town of Hilo (20 km). In the interior of the lava fountains, the white-orange color indicates maximum temperatures of about 1120°C; deeper orange in both the fountains and flows reflects decreasing temperatures (<1100°C) at edges and the surface. (b) High winds swept the exposed ridges, and the filter cannister was changed in the shelter of a p^hoehoc (lava) ridge to protect the sample from gas contamination. (c) Because of the high temperatures and acid gases, special clothing and equipment was necessary to protect the eyes. nose, lungs, and skin. Safety features included military flight suits of nonflammable fabric, fuil-face respirators that are equipped with dual acidic gas filters (purple attachments), hard hats, heavy, thick-soled boots, and protective gloves. We used portable radios to keep in touch with the Hawaii Volcano Observatory, where the area's seismic activity was monitored continuously. (d) Spatter activity in the Pu'u O Vent during the January 1984 eruption of Kilauea Volcano. Magma visible in the circular conduit oscillated in a piston-like fashion; spatter was ejected to heights of 1 to 10 m. During this activity, we sampled gases continuously for 5 hours at the west edge. Cover photo: This aerial view of Kilauea Volcano was taken in April 1984 during overflights to collect gas samples from the plume. The bluish portion of the gas plume contained a far higher density of fine-grained scoria (ash).
    [Show full text]
  • Apollo Over the Moon: a View from Orbit (Nasa Sp-362)
    chl APOLLO OVER THE MOON: A VIEW FROM ORBIT (NASA SP-362) Chapter 1 - Introduction Harold Masursky, Farouk El-Baz, Frederick J. Doyle, and Leon J. Kosofsky [For a high resolution picture- click here] Objectives [1] Photography of the lunar surface was considered an important goal of the Apollo program by the National Aeronautics and Space Administration. The important objectives of Apollo photography were (1) to gather data pertaining to the topography and specific landmarks along the approach paths to the early Apollo landing sites; (2) to obtain high-resolution photographs of the landing sites and surrounding areas to plan lunar surface exploration, and to provide a basis for extrapolating the concentrated observations at the landing sites to nearby areas; and (3) to obtain photographs suitable for regional studies of the lunar geologic environment and the processes that act upon it. Through study of the photographs and all other arrays of information gathered by the Apollo and earlier lunar programs, we may develop an understanding of the evolution of the lunar crust. In this introductory chapter we describe how the Apollo photographic systems were selected and used; how the photographic mission plans were formulated and conducted; how part of the great mass of data is being analyzed and published; and, finally, we describe some of the scientific results. Historically most lunar atlases have used photointerpretive techniques to discuss the possible origins of the Moon's crust and its surface features. The ideas presented in this volume also rely on photointerpretation. However, many ideas are substantiated or expanded by information obtained from the huge arrays of supporting data gathered by Earth-based and orbital sensors, from experiments deployed on the lunar surface, and from studies made of the returned samples.
    [Show full text]
  • The Composition of the Lunar Crust: Radiative Transfer Modeling and Analysis of Lunar Visible and Near-Infrared Spectra
    THE COMPOSITION OF THE LUNAR CRUST: RADIATIVE TRANSFER MODELING AND ANALYSIS OF LUNAR VISIBLE AND NEAR-INFRARED SPECTRA A DISSERTATION SUBMITTED TO THE GRADUATE DIVISION OF THE UNIVERSITY OF HAWAI‘I IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN GEOLOGY AND GEOPHYSICS DECEMBER 2009 By Joshua T.S. Cahill Dissertation Committee: Paul G. Lucey, Chairperson G. Jeffrey Taylor Patricia Fryer Jeffrey J. Gillis-Davis Trevor Sorensen Student: Joshua T.S. Cahill Student ID#: 1565-1460 Field: Geology and Geophysics Graduation date: December 2009 Title: The Composition of the Lunar Crust: Radiative Transfer Modeling and Analysis of Lunar Visible and Near-Infrared Spectra We certify that we have read this dissertation and that, in our opinion, it is satisfactory in scope and quality as a dissertation for the degree of Doctor of Philosophy in Geology and Geophysics. Dissertation Committee: Names Signatures Paul G. Lucey, Chairperson ____________________________ G. Jeffrey Taylor ____________________________ Jeffrey J. Gillis-Davis ____________________________ Patricia Fryer ____________________________ Trevor Sorensen ____________________________ ACKNOWLEDGEMENTS I must first express my love and appreciation to my family. Thank you to my wife Karen for providing love, support, and perspective. And to our little girl Maggie who only recently became part of our family and has already provided priceless memories in the form of beautiful smiles, belly laughs, and little bear hugs. The two of you provided me with the most meaningful reasons to push towards the "finish line". I would also like to thank my immediate and extended family. Many of them do not fully understand much about what I do, but support the endeavor acknowledging that if it is something I’m willing to put this much effort into, it must be worthwhile.
    [Show full text]
  • Handbook of Iron Meteorites, Volume 1
    CHAPTER FOUR Meteorite Craters Nobody has ever witnessed the formation of a meteor­ meteorites, and (iii) rapidly solidified metallic droplets, ite crater. Interpretations must therefore be based upon analogous to the spheroids encountered in the vicinity of measurement and comparison with artificial craters, caused Meteor Crater, Arizona (Goldstein et al. 1972; Anders et al. by known magnitudes and depths of explosives. Excellent 1973); see page 397. studies have been performed by Baldwin (1949; 1963; The bulk of the typical large lunar craters were formed 1970) who was particularly interested in the puzzling when the kinetic energy ~mv 2 of the impacting body was problems associated with the lunar craters but, as a basis for converted into thermal energy within a fraction of a his speculations, thoroughly examined several terrestrial second, resulting in an explosion. There is a very high craters and presented extensive bibliographies. Results from probability that the impacting body was thereby itself nuclear test sites have been presented by Hansen (1968) totally destroyed, melted or vaporized (Hartman & and Short (1968a, b). Krinov (1960b; 1966a, b) has dis­ Wood 1971; Ahrens & O'Keefe 1972). Fortunately, for the cussed several craters and impact holes associated with science of meteoritics and for the inhabitants of Earth, our meteorites and also devoted a liuge chapter to the Tunguska atmosphere will alleviate the impact of celestial bodies and comet, which did not produce craters at all. See page 9. through a gradual deceleration cause an important propor­ Stanyukovich &' Fedynski (1947), Nininger (1952a; 1956), tion to survive as meteorites. However, large and dense Shoemaker (1963) and Gault et al.
    [Show full text]
  • Lunar Craters Named in Honor of Apollo 8 5 October 2018
    Lunar craters named in honor of Apollo 8 5 October 2018 The Apollo 8 mission took place from 21 to 27 December 1968. After completing 10 orbits around the Moon on Christmas Eve, broadcasting images back to Earth and giving live television transmissions, the crew returned to Earth and landed in the Pacific Ocean. The Working Group for Planetary System Nomenclature (WGPSN) of the International Astronomical Union, who named the craters, is the authority responsible for the naming of planetary features in our Solar System. The two named craters were previously designated by letters. The Earthrise color photograph taken by astronaut William Anders. It depicts the moment that our shiny blue Earth came back into view as the spacecraft emerged out of the dark from behind the grey and barren Moon. This is arguably the most famous picture taken by Apollo 8. It became iconic and has been credited with starting the environmental movement.Two of the crates seen in this photo have just been named by the Working Group for Planetary System Nomenclature (WGPSN) of the International Astronomical Union. Credit: NASA/IAU The newly named craters are visible in the The Working Group for Planetary System Nomenclature foreground of the iconic Earthrise colour of the International Astronomical Union has officially photograph taken by astronaut William Anders. It approved the naming of two craters on the Moon to commemorate the 50th anniversary of the Apollo 8 depicts the moment that our shiny blue Earth came mission. The names are Anders’ Earthrise and 8 back into view as the spacecraft emerged out of Homeward.
    [Show full text]
  • On the Moon with Apollo 16. a Guidebook to the Descartes Region. INSTITUTION National Aeronautics and Space Administration, Washington, D.C
    DOCUMENT RESUME ED 062 148 SE 013 594 AUTHOR Simmons, Gene TITLE On the Moon with Apollo 16. A Guidebook to the Descartes Region. INSTITUTION National Aeronautics and Space Administration, Washington, D.C. REPORT NO NASA-EP-95 PUB DATE Apr 72 NOTE 92p. AVAILABLE FROM Superintendent of Documents, Government Printing Office, Washington, D. C. 20402 (Stock Number 3300-0421, $1.00) EDRS PRICE MF-$0.65 HC-$3.29 DESCRIPTORS *Aerospace Technology; Astronomy; *Lunar Research; Resource Materials; Scientific Research; *Space Sciences IDENTIFIERS NASA ABSTRACT The Apollo 16 guidebook describes and illustrates (with artist concepts) the physical appearance of the lunar region visited. Maps show the planned traverses (trips on the lunar surface via Lunar Rover); the plans for scientific experiments are described in depth; and timelines for all activities are included. A section on uThe Crewn is illustrated with photos showing training and preparatory activities. (Aathor/PR) ON THE MOON WITH APOLLO 16 A Guidebook to the Descartes Region U.S. DEPARTMENT OF HEALTH. EDUCATION & WELFARE OFFICE OF EDUCATION THIS DOCUMENT HAS BEEN REPRO- DUCED EXACTLY AS RECEIVED FROM THE PERSON OR ORGANIZATION ORIG- grIl INATING IT POINTS OF VIEW OR OPIN- IONS STATED DO NOT NECESSARILY REPRESENT OFFICIAL OFFICE OF EDU- CATION POSITION on POLICY. JAI -0110 44 . UP. 16/11.4LI NATIONAL AERONAUTICS AND SPACE ADMINISTRATION April 1972 EP-95 kr) ON THE MOON WITH APOLLO 16 A Guidebook to the Descartes Region by Gene Simmons A * 40. 7 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION April 1972 2 Gene Simmons was Chief Scientist of the Manned Spacecraft Center in Houston for two years and isnow Professor of Geophysics at the Mas- sachusetts Institute of Technology.
    [Show full text]
  • Hoshyar Zebari Thomas R. Pickering Tibor Tóth Man-Made Crater Ever Created
    issue 20 july 2013 20 july issue www.ctbto.org We Are Our Own Enemy, Alamogordo, 20 CTBTO New Mexico, USA,1945 by SpectruM Elin ctbto Magazine issue 20 | July 2013 O’Hara Slavick this drawing by elin o’Hara slavick takes as its reference an aerial photograph from the los alamos national laboratory archive of the crater formed by the first atomic explosion. on 16 July 1945 the trinity test took place at the alamogordo test Range in new Mexico, usa. it was the first nuclear explosion in history. the detonation is credited as the beginning of the atomic age. see page 34 in this issue for more information about the artist and her work. Saucer-shaped craters caused by subsidence following the underground nuclear tests at the Nevada Test Site. Courtesy of U.S. Department of Energy. ctbto spectrum ctbto Crater from the 1962 “Sedan” nuclear test, the largest HosHyar Zebari tHomas r. pickering tibor tótH man-made crater ever created. Courtesy of U.S. Department of Energy. iRaQ’s FoReign MinisteR FoRMeR u.s. undeR secRetaRy CTBTO eXecutiVe secRETARy oF state FoR Political aFFaiRs The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all nuclear explosions. It opened for signature on 24 September 1996 in New York. As of June 2013, 183 countries had signed the Treaty and 159 had ratified. Of the 44 nuclear capable States which must ratify the CTBT for it to enter into force, the so-called Annex 2 countries, 36 have done so to date while eight have yet to ratify: China, the Democratic People's Republic of Korea, Egypt, India, Iran, Israel, Pakistan and the United States.
    [Show full text]
  • Enhanced Warfighters: Risk, Ethics, and Policy
    Enhanced Warfighters: Risk, Ethics, and Policy Maxwell J. Mehlman Case Research Paper Series in Legal Studies Working Paper 2013-2 Jan., 2013 This paper can be downloaded without charge from the Social Science Research Network Electronic Paper Collection: http://ssrn.com/abstract=2202982 For a complete listing of this series: http://www.law.case.edu/ssrn Electronic copy available at: http://ssrn.com/abstract=2202982 CASE WESTERN RESERVE UNIVERSITY Enhanced Warfighters: Risk, Ethics, and Policy Prepared for: The Greenwall Foundation Prepared by: Patrick Lin, PhD Maxwell J. Mehlman, JD Keith Abney, ABD California Polytechnic State University, San Luis Obispo College of Liberal Arts Philosophy Department Ethics + Emerging Sciences Group Case Western Reserve University School of Law School of Medicine The Law-Medicine Center Prepared on: January 1, 2013 Version: 1.0.0 Electronic copy available at: http://ssrn.com/abstract=2202982 ▌i Index Executive summary iii Disclosures iv 1. Introduction 1 1.1. Purpose 2 1.2. Background 3 1.3. Questions 8 2. What is human enhancement? 11 2.1. Controversies 12 2.2. Working definition 17 2.3. Variables 18 2.4. Technology survey 21 3. Law and policy 28 3.1. International humanitarian law 28 3.2. US domestic law 36 3.3. Operations 38 4. Bioethics 43 4.1. Research model 44 4.2. Medical model 50 4.3. Public-health model 54 5. Risk Assessment 57 5.1. Risk-benefit model 57 5.2. Risk factors 61 6. A hybrid framework 66 6.1. Legitimate military purpose 66 6.2. Necessity 67 6.3. Benefits outweigh risks 67 Enhanced Warfighters: Risk, Ethics, and Policy Copyright 2013 © Patrick Lin, Maxwell J.
    [Show full text]
  • Illustrations
    G. K. Gilbert. Ralph B. Baldwin. Courtesy of Pamela Baldwin. Gene Simmons, Harold Urey, John O'Keefe, Thomas Gold, Eugene Shoemaker, and University of Chicago chemist Edward Anders (left to right) at a 1970 press conference. NASA photo, courtesy of James Arnold. Ewen Whitaker and Gerard Kuiper (right) during the Ranger 6 mission in 1964. JPL photo, courtesy of Whitaker. Eugene Shoemaker at Meteor Crater in 1965. USGS photo, courtesy of Shoemaker. Key photo centered on Copernicus (95 km, 10° N, 2 0° w) on which Eugene Shoemaker based his early geologic mapping and studies of Copernicus secondary-impact craters. Rima Stadius, a chain of secondaries long thought by most experts to be endogenic , runs roughly north-south to right (east) of Copernicus. Telescopic photo of exceptional quality, taken by Francis Pease with loa-inch Mount Wilson reflector on 15 September 1929. Mare-filled Archimedes (left, 83 km, 30° N, 4° w) and postmare Aristillus (above) and Autolycus (below), in an excellent telescopic photo that reveals critical stratigraphic relations and also led ultimately to the choice of the Apollo 15 landing site (between meandering Hadley Rille and the rugged Apennine Mountains at lower right). The plains deposit on the Apennine Bench, between Archimedes and the Apennines, is younger than the Apennines (part of the Imbrium impact-basin rim) but older than Archimedes and the volcanic mare. Taken in 1962 by George Herbig with the rzo-inch reflector of Lick Observatory. Features of the south-central near side that have figured prominently in lunar thinking, including Imbrium sculpture at Ptolemaeus (p, 153 km, 9° 5, 2° w); hummocky Fra Mauro Formation its type area north of crater Fra Mauro (FM, 95 km, 6° 5, 17° w); and Davy Rille, the chain of small craters extending left (west) of the irregular double crater Davy G (D).
    [Show full text]
  • 19890006473.Pdf
    1. ASPECTS OF LITHOSPHERIC EVOLUTION ON VENUS II. THERMAL AND COLLISIONAL HISTORIES OF CHONDRITE PARENT BODIES Robert E. Grimm B.A., University of Tennessee (1 983) SUBMITTED TO THE DEPARTMENT OF EARTH, ATMOSPHERIC, AND PLANETARY SCIENCES IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY October 1988 0 Massachusetts Institute of Technology 1988 Signature of Author Department of Earth, Atmospheric, and Planetary Sciences Certified by Sean C. Solomon Thesis Supervisor Accepted by Theodore R. Madden Chairman, Department Committee LhASA-CR-le4568) PA69 1: ASEIC'IS CP N 8 9- 1f 8 4 4 I~!ZBOSP€IER~C€VCLt!IION GN VELC5. FAET 2: 1EERtlAL AhD CCLLIEICNAL HI5'lCE1EE GP CIICNDSiI'IE FAbENI tOlj1IS Ph.C. Skesis Dnclas (tassachusettr lngt- cf Tech.) 229 p G3/91 0178596 2 1. ASPECTS OF LITHOSPHERIC EVOLUTION ON VENUS II. THERMAL AND COLLISIONAL HISTORIES OF CHONDRITE PARENT BODIES Robert E. Grimm Submitted to the Department of Earth, Atmospheric, and Planetary Sciences on October 25, 1988, in partial fulfillment of the requirements of the Degree of Doctor of Philosophy in Geophysics ABSTRACT This thesis consists of two principal sections which address the geological evo- lution of distinctly different kinds of solar system objects. Venus, the second largest of the terrestrial planets, has been observed over the past decade by orbital radars on both American and Soviet spacecraft. These surface measurements provide clues to the structure and evolution of the lithosphere. The parent bodies of chon- dritic meteorites, thought to resemble asteroids, represent the other end of the size spectrum of terrestrial objects.
    [Show full text]
  • Envision – Front Cover
    EnVision – Front Cover ESA M5 proposal - downloaded from ArXiV.org Proposal Name: EnVision Lead Proposer: Richard Ghail Core Team members Richard Ghail Jörn Helbert Radar Systems Engineering Thermal Infrared Mapping Civil and Environmental Engineering, Institute for Planetary Research, Imperial College London, United Kingdom DLR, Germany Lorenzo Bruzzone Thomas Widemann Subsurface Sounding Ultraviolet, Visible and Infrared Spectroscopy Remote Sensing Laboratory, LESIA, Observatoire de Paris, University of Trento, Italy France Philippa Mason Colin Wilson Surface Processes Atmospheric Science Earth Science and Engineering, Atmospheric Physics, Imperial College London, United Kingdom University of Oxford, United Kingdom Caroline Dumoulin Ann Carine Vandaele Interior Dynamics Spectroscopy and Solar Occultation Laboratoire de Planétologie et Géodynamique Belgian Institute for Space Aeronomy, de Nantes, Belgium France Pascal Rosenblatt Emmanuel Marcq Spin Dynamics Volcanic Gas Retrievals Royal Observatory of Belgium LATMOS, Université de Versailles Saint- Brussels, Belgium Quentin, France Robbie Herrick Louis-Jerome Burtz StereoSAR Outreach and Systems Engineering Geophysical Institute, ISAE-Supaero University of Alaska, Fairbanks, United States Toulouse, France EnVision Page 1 of 43 ESA M5 proposal - downloaded from ArXiV.org Executive Summary Why are the terrestrial planets so different? Venus should be the most Earth-like of all our planetary neighbours: its size, bulk composition and distance from the Sun are very similar to those of Earth.
    [Show full text]