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SEPTEMBER 2015 | VOL 173 | NO 8

HIGH-TECH MATERIALS & PROCESSES BERYLLIUM FOR SPACE TELESCOPES P.20

METALLURGY LANE 34 PIONEERS IN RESEARCH—PART I

MS&T15 SHOW PREVIEW 37 OCTOBER 4-8, COLUMBUS, OHIO

ASM FOUNDATION 49 ANNUAL REPORT 20 SPACE-AGE MATERIALS SPACE-AGE

BERYLLIUM OPTICS ENABLE ADVANCED SPACE TELESCOPES Beryllium won a lengthy competition as the material of choice for the mirrors on the James Webb Space Telescope, set to launch in 2018.

Don Hashiguchi, FASM* James Marder, FASM* Roger Paquin* Materion Corp. Thermacore Inc. Elmore, Ohio Rostraver, Pa. Consultant Grantham, N.H.

*Member of ASM International 21 ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2015 . However, . However, [1] The reflecting mirrors that act as mirrors The reflecting Historically, Be was not considered not considered was Be Historically, the compound eyes of the James Webb the compound among the most are Telescope Space optics ever space and complex precise the telescope’s Essential to fabricated. of the characteristics are performance up that make segments 18 adjustable Specifying the 6.5-m primary reflector. in high perfor- new ground Be broke mance space optical materials develop- materials optical space mance departure ment, a significant was and Telescope the glass Hubble Space from the JWST. primary that preceded even during the 1970s, many However, Be optics. featured telescopes space to the path cleared mirrors These early polishability and stability the improved of the JWST. of satellite mirrors and structures con- and structures mirrors of satellite save even thought about how to stantly these a single pound. Beryllium affords poten- to the opportunity designers of pounds. tially save hundreds BERYLLIUM SPACE SPACE BERYLLIUM TELESCOPE HISTORY due to its significant weight and stiff- weight significant its due to devel- a concentrated ness advantages, its overcome to worked opment effort During the 1980s, the Stra- limitations. the emphasized Initiative Defense tegic lightweight, high extremely need for It satellites. surveillance performance initiative Wars” during the “Star was of Be as a mirror that the shortcomings and recognized generally were material possible solutions imagined. Designers are so much smaller. Surprisingly, , steel, Surprisingly, smaller. so much are have sim- and Ti alloys all Al, Ni alloys, while the Mg and ULE, to ilar ratios all of of Be surpasses specific stiffness 1. in Table these, as shown material optical an ideal which is much eas- —on earth at 1 g, it at —on earth 163 30 25 26 1.85 2.21 2.70 1.74 null figuring, 2 Specific stiffness measures how Specific stiffness measures In order to minimize mass, using a minimize to In order 3 /s 2 /K 11.4 0.03 22.5 24.8 optical figure optical -6 m 6 10 g/cm low density material is an obvious first is an obvious first low density material of ULE is slightly less The density step: conventional than that of Al. However, such as ULE and Al are materials mirror 31% than Be, which is much heavier than than Al and 18% lighter lighter than 6% lighter ULE. is stiffness, or is another factor Be. Yet which is equally modulus of elasticity, how it measures because important deformation resists a material Beryllium under load. is 400% stiffer than both Al and ULE and 670% stiffer of than Mg. Specific stiffness—the ratio the density—determines modulus to efficiency of a material, than five that Be is more and it is clear in than the other materials times better this regard. its shape maintains well a structure such as gravity, of forces in the face a After launch, or maneuvering g’s. shape— its desired is polished to mirror or the material criteria very criteria reliably—but the material devel- as O-30 Be, which was not as well mirrors. satellite for oped specifically prop- the important 1 compares Table and Be, ULE, aluminum, erties of O-30 magnesium. changes figure in the 0-g orbital envi- in the 0-g orbital figure changes causes release” ronment. This “gravity but with change, only a slight figure these changes, very lightweight mirrors of wavelengths in fractions measured substantially of light, be enough to can Grinding and pol- the image. distort what will to on earth ishing the mirror is in space figure the correct become called ier with a material featuring a high spe- featuring ier with a material the distortions cific stiffness because 10 U U D . The new [2] , while limitations of the , while limitations Density Modulus E GPa 303 68 68 45 [1] Property Symbol Units O-30 Be ULE 6061 Al Mg

Specific stiffness E/ aunching objects into earth’s orbit earth’s objects into aunching so every expensive, is enormously saves significantpound removed The most obvious requirements The most obvious requirements Low thermal expansion glass, thermal expansion Low Thermal conductivity k W/m•K 208 1.3 167 156

Coeff. of thermal expansion of thermal Coeff. for space optics include low mass, high optics include space for when contraction stiffness, predictable and cryogenic , to cooled a highly be polished to the ability to These characteris- surface. reflective and discussed recognized tics were as 1966 as early as design parameters by Barnes available hot pressed (VHP) hot pressed vacuum available later, A decade also detailed. Be were with Be mir- telescopes numerous after in orbit, hot isostatic already were rors Be optics for advocated was pressing Be material of HIP’d and an evaluation the Be from with VHP’d in comparison published same powder was TABLE 1 — ROOM PROPERTIES OF MIRROR MATERIALS OF MIRROR PROPERTIES 1 — ROOM TEMPERATURE TABLE BERYLLIUM PROPERTIES: PROPERTIES: BERYLLIUM IDEAL FOR SPACE cost. When considering materials for the for materials When considering cost. a (JWST), Telescope Space James Webb deter- to place took lengthy competition and beryllium wasmine the best choices This the mirrors. for specified ultimately the developmentalarticle documents that decision. It took up to history leading Be— make to of improvements decades powder/ O-30 atomized in particular compo- (HIP’d) pressed hot isostatically polish- isotropic, nents—homogeneous, stable,able, thermally and dimensionally and above all, predictable. such as the ULE fused silica (Corning’s (Corning’s silica such as the ULE fused Glass) Expansion Low Code 7972 Ultra Tele- the Hubble Space for selected of several meets primary mirror, scope material was found to be superior and to found was material for the specifications meets therefore mirrors. infrared L 22 Space telescopes serve many pur- and after WWII show that it could be the 1972. Later versions include the The- poses, ranging from weather and astro- right material for mirrors and structures matic Mapper instrument, which used nomical exploration to in the new field of space . S-200F, an improved version of S-200E. and a variety of scientific and military One of the earliest applications of Be An SEM micrograph of the powder and applications. Increasing demand for mirrors in space was the Multi-Spectral an optical micrograph of consolidated higher resolution, lighter weight, and Scanner for the Landsat earth imag- S-200F are shown in Figs. 1 and 2, fea- greater dimensional stability has driven ing satellite in which the S-200E grade turing an content of approxi- the choice of many systems to Be, but was used. The earliest applications mately 1% BeO. with increased emphasis on dimen- were electroless plated because Another early space optical appli- sional stability and polishability. uncoated S-200E could not be polished cation was VISSR, the Visible Infrared Beryllium use for light, stiff, low to the required finish. The first of these Spin Scan Radiometer on the GOES, moment of inertia applications during Landsat satellites was launched in Geostationary Operational Environ- mental Satellite[3]. The scan mirror was particularly critical in this application, and any bending as the mirror reversed direction would have distorted the image. The extremely low moment of inertia Be scan mirror provided the required image stability, whereas con- ventional materials could not. The three mirrors for the early VISSR tele- ASM Invites You! scopes were plated with electroless [4]

ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2015 & PROCESSES MATERIALS ADVANCED nickel for polishability . The first of these satellites was launched in 1974 ASM 102nd Annual and GOES satellites are still produced Business Meeting and launched. The VISSR instrument was replaced by a multispectral scan- Monday, October 5 ner that continues to use lightweight Be 4PM-5PM mirrors, with improved Be grades speci- Get exclusive insight on the ASM future vision, learn what ASM and the Leader- fied as they became available. ship have accomplished this year and recognize officers newly elected for the One of the first space telescopes 2015-2016 term by attending the annual meeting. to use an engineered grade of Be was IRAS, the InfraRed Astronomical Satel- Future ASM executive leaders, members and guests are lite, launched in 1983. It had a 60-cm strongly encouraged to attend. primary mirror of I-70A Be and was polished bare, without a Ni coating. IRAS was one of the first athermalized telescopes where all components, including the mirrors and structure, were made of Be. This ensured that the entire assembly contracted uniformly to the 10K operating temperature. The coefficient of thermal expansion of Be ASM Awards Dinner at that temperature is virtually zero, Tuesday, October 6 | 6:30PM-9:30PM which guarantees dimensional stability President’s Reception Starting at 9:30PM with any minor temperature variations. Join us in celebrating the wonderful accomplishments of this year’s award The IRAS primary mirror did, however, recipients and the 2015 Class of Fellows. Tickets, which include the President’s exhibit significant thermal figure distor- Reception following the dinner, can be purchased via the MS&T registration form. tion at the cryogenic temperature, but that distortion only minimally affected measurements at the shortest wave- MS&T 15 length of 12µm. At longer wavelengths, the telescope was diffraction limited. MATERIALS & TECHNOLOGY www.matscitech.org The successor to IRAS was the Shuttle InfraRed Telescope Facility, SIRTF, now designated Spitzer Space Telescope, one of NASA’s four great ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2015 23 . [6] Each of the 18 primary seg- mirror ments (plus spares) measures 1.3 m and measures ments (plus spares) (88 lb). 40 kg Seg- weighs approximately figure a surface polished to ments were of 24.2 nm rms and include accuracy of spherical Be powder consolidated by Be powder consolidated of spherical for material the ultimate HIP—provided used are mirrors Four mirrors. the JWST including the 18 segment in the JWST, 738-mm secondary, 6.5-m primary, and a 172.5-mm738 x 517-mm tertiary, the stabilize to mirror steering fast for -coated are All mirrors image. 6 Figure reflectance. infrared enhanced and the com- shows the finished mirrors JWST plete Polarized light photomicrograph of S-200F grade beryllium. of S-200F grade light photomicrograph Polarized Polarized light photomicrograph of I-70H grade of beryllium grade of I-70H light photomicrograph Polarized Fig. 2 — Fig. 4 — to Higher purity input powder in comparison by HIP. consolidated particles. oxide by fewer white S-200F is illustrated The low oxide content and resid- content The low oxide ual inhomogeneity found in I-70H (0.7% found ual inhomogeneity even fur- be reduced BeO) needed to a viable become Be could ther before because mirrors, JWST for candidate wave- at much shorter they operate step—development lengths. The next genic temperatures, the correction to to the correction temperatures, genic polished into was error the small figure cryo called null in a process the surface nor figuring. While neither the scatter would of this telescope figure optical limited a diffraction for be acceptable it exceeded system, visible wavelength infra- far the mid and for specifications being observed. wavelengths red . The excellent surface finish surface . The excellent SEM photomicrograph of I-70 grade beryllium of I-70 grade powder pro- SEM photomicrograph 500× SEM photomicrograph of S-200F grade blocky shaped of S-200F grade 500× SEM photomicrograph [5] and optical figure obtained, as well as obtained, figure and optical thermal dimensional the insignificant at 10K, observedinstability when tested of the improved result a direct were quality achieved by the HIP material of figure the optical Because process. at cryo- tested the primary was mirror duced to a higher purity in comparison to S-200F grade that improved S-200F grade to a higher purity in comparison to duced by is produced Powder surface. a polished mirror produce the ability to grinding. impact Fig. 3 — observatories. With its 85-cm diameter, With its 85-cm diameter, observatories. polished primary made of mirror bare I-70 Be (I-70H), this HIP consolidated at 5.5K. An operates all-Be telescope light micrograph SEM and associated shown in Figs. 3 and 4. The of I-70H are shown in Fig. 5 is the proto- telescope Lab- Propulsion at Jet type being tested oratory beryllium powder produced by impact grinding. All images courtesy of courtesy grinding. All images beryllium by impact powder produced 5 and 6. except Materion Fig. 1 — 24 ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2015 going random vibration testing HISTORICAL DEVELOPMENT BERYLLIUM POWDER: accuracy. polish andmeasure, hasasimilarfigure mirror, thoughmuchmore difficultto Theconvex1000 Åthick. secondary a vacuum deposited gold coating, Fig. 5— 50s, beryllium powder was produced50s, beryllium mechanical properties. Inthe1940s and while thefinergrain size alsoimproves the coefficient ofthermalexpansion, entation improves isotropy, particularly The more random grain ori- andcrystal nearly random-structured material. the late 1940sto produce finegrained, improve properties. chips priorto powderprocessing helps ties. However, theingot into in machining,andoverall poorproper- results inproperty anisotropy, difficulty ual toward thecenter. This inward from theingot wall andresid- with large columnar grains growing lium features atypical structure, uum step. Statically cast beryl- well asrecycled Beare inputto thevac- ide into metallic Be.Newlyrefined as from hydrox- thereduction ofberyllium and thatmightbecarried over melting removes residual magnesium as part oftherefining process. Vacuum starts withvacuum meltingandcasting Powder was usedin processingBeryllium traditionally Prototype SIRTF telescope under- [5] . back into theimpact stream. This separated byairelutriation andfed oversized powderparticles could be was alsosemi-continuous because attrition milledpowder. Thisprocess exhibit ablockiershapethanball or the chipsinto powderparticles, which from thenozzle. Theimpact shatters is dried,andthencools asitexpands Be chipsagainst aBetarget. Theair and useshighvelocitygas to propel production process inthelate 1970s lium powderwas introduced asa basal plane. flake-like structure byfracture onthe produced powderparticles withaslight tal isthebasal planeandthisprocess The weakest orientation oftheBecrys- and was sheared into powderparticles. rotating plates beryllium andstationary flour mills.Thechippassed between chip was fed into adevice similarto old continuous process inwhichberyllium grinding media.Attrition millingwas a resulted iniron contamination from the this was acostly batch operation and sheared into finepowderflakes, but wasened steel. crushedand Beryllium grinding mediagenerally madeofhard- rotating canister filledwithchipsand attrition .Ballmillingusesa by twodifferent processes—ball and Fig. 6— them bothlightandstiff. different mirror segments asseenfrom the rear showingthehoneycomb structure thatmakes tion ofthetelescope mirror segments. Onthebottom opticswith18primary row are the three Impact grindingto produce beryl- JamesWebbSpace Telescope anditsmirrors isblasted into smalldroplets by Astream1980s for beryllium. ofliquid gas atomization, developedinthelate sense for makingpowderwas inert solution. Therefore, additionalpolishing isnota and changes oneach cooling cycle. slightly. Scattering isunpredictable regions actually deform oneanother the mirror iswarmed andcooled, these it inoneuniform direction. Eachtime tering thebeam rather than reflecting light ataslightlydifferent angle,scat- that each region isreflecting abeam of orange-peel appearance, whichmeans between regions givesthesurface an polished mirror cools, thedifference different orientations. Whenthe solid, differently thanadjoiningregions with tation. Eachoftheseregions behaves regions orien- havingthesamecrystal of cards orsheets ofmica, withlarge them, theycan stack uplike adeck are loaded into apress to consolidate flakes are allbasal planes.Whenflakes idation into asolid.Theflatsurfaces of of containers inpreparation for consol- was important duringvibratory loading tal structure thanotherprocesses. This powder shapelessrelated to thecrys- oxygen contamination, andproduced a process improvement reduced and [6] . Bottom right showsanartist’s concep- The process thatmadethemost ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2015 25 , and , diagrams diagrams (CCT) (DTTT) Technologists who worked on mir- worked who Technologists www.tainstruments.com better than uniaxial vacuum hot press- vacuum uniaxial than better of consolidated ing. The in Fig. 8. O-30 is shown beryllium that reported in the 1960s rors In unsuccessful. trials were atomization very levels resulted. high oxide particular, spent making certain was Much effort to airtight was that the new atomizer level. HIP’ing beryl- the oxygen control been tried, butlium powder had also when formed were voids because failed , continuous-cooling-transformation continuous-cooling-transformation , (TTT) Discover More Discover Capability Research Steel time-temperature-transformation after deformation deformation after time-temperature-transformation as well as -strain curves. Powerful inductive heating and an inductive Powerful curves. as stress-strain as well 4000 K/s up to heating rates enable system helium quench innovative of the extremes capture as high as 2500 K/s to and rates conditions. modern processing DIL 805 Quenching and Deformation Dilatometer Deformation and DIL 805 Quenching provide dilatometers deformation DIL 805-series quenching and The of heating, the widest range over measurements the most accurate the most sophisticated for allowing conditions, and deformation cooling, The conditions. processing and optimization of steel characterization the construction of time-temperature- for critical data DIL 805 provides transformation is poured into a metal can that is evacu- that can a metal into is poured into placed This is then and sealed. ated with the HIP unit,is pressurized which pressure A typical and heated. argon is contents and its the can compressing 30,000 psi and temperatures 15,000 to The solid be applied. can 2000°C to is removed the can after that emerges of voids. Another ad- free is completely is ap- the pressure of HIP is that vantage the so it maintains plied in all directions of the final product non-directionality . us, Ohio, head- us, Ohio, [2] . [7] Columb Although HIP was developed by Although HIP was Spherical particles pack together together pack particles Spherical Once the powder is made, it is powder is made, it is the Once Battelle at its Battelle quarters in the 1940s for cladding nu- cladding in the 1940s for quarters its uses have rods, fuel reactor clear include casting to expanded greatly powder consolidation, densification, powder bonding. In HIP, and diffusion a stream of gas in a two-story chamber, in a two-story chamber, of gas a stream Helium, particles. in spherical resulting were nitrogen ultimately and argon, An SEM gases. atomization all used as is Be powder atomized of micrograph 7. shown in Fig. crystal orientation. to with no relation ori- is randomly particle each Because develop. can regions no large ented, level themselves out,Properties - surface. uniform an essentially ing to HIP consolidation, with In conjunction mirror predictable in a this results all in contraction with equal thermal particles oxide In addition, directions. mirror of a the performance degrade acts as a particle oxide each because Therefore, source. scattering separate improved into translates lower oxide The solid optical performance. optical optical the atomized blanks made from O-30, have of beryllium powder, grade less than 0.35% beryllium Recall oxide. that I-70A and S-200F have 0.7% and pow- Atomized respectively. 1% oxide for choice an excellent der is therefore material a mirror compacted into a solid. Historically, a solid. Historically, into compacted into hot pressed vacuum powder was roughly from ranging solid cylinders Aerospace 72 inches in diameter. 8 to the highest level requiring components made from density were of stiffness to the Space example, For these cylinders. machined were doors Shuttle umbilical cyl- hot pressed large-diameter from frame, the window as were inders, The base. and navigation brakes, Spheres Inertial Reference Advanced ICBM (inter- of the Peacekeeper (AIRS) missile) were ballistic continental hot vacuum machined from likewise beryllium. pressed This hot pressing less than 0.5% voids, leaves method them. eliminate but does not totally all voids had Telescope, the JWST For use of hot to leading be eliminated, to (HIP) pressing isostatic 26 ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2015 powder. Fig. 7— When StrainMeasurementisCritical… Have you consideredtheconsequences ofnot measuringstrainproperly? 825 University Avenue, MA02062 Norwood, SEMphotomicrograph ofinertgas atomized O-30grade Be | 1.800.564.8378 | go.instron.com/aboutstrain evident. cal priorparticle boundariescontaining multiplegrains perparticle are consolidated byHIPfrom inertgas powder. atomized beryllium Spheri- Fig. 8— Polarized lightphotomicrograph ofO-30Hgrade beryllium go.instron.com/aboutstrain Measurement Solutionsat Learn moreaboutStrain TRUST Instron 27 ADVANCED MATERIALS & PROCESSES | SEPTEMBER 2015 1991.

p 1485, Proc. SPIE, Reflective Proc. Class 0.5 load cells Class 0.5 load cells 1 msec (1 kHz) testing efficient, user interface for more testing effective curves with Accurate stress-strain High-speed data sampling up to and strain-controlled stress- Precise safety measures Comprehensive with a refined Easy-to-use software Shimadzu’s AGS-X AGS-X Shimadzu’s Series features: Q Q Q Q Q In addition, a comprehensive selection selection In addition, a comprehensive plates, jigs, of grips, compression extensometers, and other accessories to allow configurations to be tailored almost any application. 8. Creation Marder, D.A. J.M. Gildner and Berylliumof Aspheric Surfaces Optical Con- Pressing the Hot Isostatic in Directly Process, solidation Earth for Materials Optical and Refractive Applications, and Space Force Systems Command, Wright Wright Command, Systems Force AFB, 1991. Patterson . of floor of floor , p 3356, , p 3356, AGS-X Series Learn more. Call (800) 477-1227 or visit us online at www.ssi.shimadzu.com/AGSX Adaptable to Countless Applications Shimadzu Scientific Instruments Inc., 7102 Riverwood Dr., Columbia, MD 21046, USA Shimadzu Scientific Instruments Inc., 7102 Riverwood Dr., Practical, Cost-effective Cost-effective Practical, Testers Electromechanical Combining advanced specifications modern design, with an affordable, Shimadzu’s and tabletop universal testers delivers practical solutions across a wide range of applications. By incorporating multiple control options, load cells with maximum 1 N to 300 kN, and capacities from the utmost in safety considerations, the AGS-X series is the choice for testing efficient more easier, Telescope, NASA website, NASA website, Telescope, www.jwst.nasa.gov. 7. Marder, and J.M. D. Hashiguchi WL- BerylliumSpherical Powder, Air Wright , TR-91-8017, 6. James Webb Space Explore 1998. Telescopes and Instruments V and Instruments Telescopes Space Space , Space Space , Vol 97, Vol James Marder is James Marder 1118, 1989. Proc. SPIE Proc.

Proc. SPIE Proc. ~AM&P , Vol 5, No. 12, p 1883, 5, No. , Vol Vol 50, p Vol Design, Manufacture and Design, Manufacture , The authors would like to acknowl- to like would The authors The James Webb Space Telescope Telescope The James Webb Space red Telescope Facility, Facility, Telescope red in the Use of Beryllium for Mirrors, in the Use of Beryllium Mirrors, for Applied Optics 1966. 3. Gunter’s Space Page, GOES 4, 5, 6, G, 3. Page, Space Gunter’s 7, http://space.skyrocket.de/doc_sdat/ goes-d.htm. 4. a Optics for Campbell, Metal J.C. Radiometer, Spin-Scan Visible Infrared SPIE Proc. p 0065, 1976. Infra- 5. al., The Space et Fanson, J.L. 2. E.W. Gossett, Jr., et al., Evaluation of al., Evaluation et 2. Gossett, Jr., E.W. Scatter Beryllium Low Hot Isostatic for Cryogenic Optics, Optics, of Metal Application References Considerations Barnes, Jr., 1. W.P. Qualifica- and Space Materials Optical tion of Optics, edge the cooperation of Materion Corp. Corp. of Materion the cooperation edge of this article. In addi- in the preparation of Mark Hashigu- tion, the contributions the for of Materion chi and Daniel Slates essential. support were metallographic For more information: more For Acknowledgment vice president of materials and process and process of materials president vice Inc., 440 Jon- development, Thermacore 15012, PA Belle Vernon, athan Willey Rd., 724.379.1490, j.m.marder@thermacore. www.thermacore.com. com, the solid mirror blanks were heat treated, treated, heat were blanks mirror the solid disease.” as “HIP to referred was which recog- it was developed, was When O-30 on entrained water that nized the were particles of powder the surface “ther- now called of HIP disease, cause was The process porosity.” mally induced water the eliminate developed to further the disease. molecules and therefore launch in 2018. It is is scheduled for an dramatic as provide to expected over the Hubble as the improvement observato- Hubble did over previous of berylliumries. The evolution as the substan- a will provide material optical of the the success to tial contribution new telescope.