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Report No. BMU7^i Metallurgy and Ceramic*
Cam ttlk W«Wdi*|*ll % % MECHANICAL PROPERTIES OF ZIRCONIUM-TIN ALLOYS
A. D. Schwopt W. Chubb
M « e f A 3 ^
M W I U M c a l J . * - /£ >
V ^ M e M e tmm riw O l f l e e e l Tm Im Im I W v i t M
U , O . C .
December
HAT TELLE MEMORIAL INSTITUTE 505 King Avenue Columbus lf Ohio
151 — ------
H
TABLX OF CONTENTS
Put
ABSTRACT...... T * INTRODUCTION. « ...... 9
EXPERIMENTAL WORK...... • 9
Fabrication of the Alloy* • . « ...... • •••••• 9 Tensile T e s tin g ...... 10 Hot-Hardness Data...... 10 Impact Data ...... *9 Corrosion Data ...... *0
CONCLUSIONS . * ...... 20
LIST OF TABLES
Tahiti. Analyst* of Spoof t Zirconium-Tin Alloys • • • • • • • 10
T a h iti. Hardness Data for Spongt 2irco®Jum-Tln Alloy* • . . . 10
Table J. Tensile Properties of Sponge Zlrconlum-Tin Alloy* • • 11
Table 4. Hot-Hardness of Spongt Zirconium-Tin Alloy*. . . . . 16
Table 5. Impact Properties of Sponge Zirconium-Tin Alloys • .19
a * 4*
LIST or FIGURES
P m
Figure 1, Effect of Tin on Tensile Prop*riles of Sponge Zirconium At Room Temperature ,.«•••• 12 figure 2, Effect of Tin on Tensile Properties of Sponge Zirconium at 260 C «•••••• • •••••IS
figure S« Effect of Tin on Tensile Properties of Sponge Zirconium at 500 C •••••••• • ••••14
figure 4, Hsrdnese of Induction-Melted Sponge Zirconium Alloys st Elevated Tempersture*...... 17
figure 5« Relation Between Hardness and Tensils Strength of Induction-Melted Sponge Zirconium- Tin Alloys Up to 500 C . • , ...... IS
&£« m m si ? A * The michinlc»lVropfrtl«i and corrosion nsliUnct of induction- melted, aiecoaiom-tin aUo«e l^vjt. been determined, Tht alloy* lnveati- > gaUd contained from aeto to five pe* eeat Wind up to 0, 3 fM deal f i U a, Tht aie& ttem uatd was Unittd State* Bureau of Miaea aponge. aUaenUim* The mechanical propertiea Investigated include the tenailti hot-berdneee, and impact propertiea. ( _ INTRODUCTION
Of all the binary aircoalum alloy* that have boon investigated to dale, non# havo shown quit* the immediate promt#* of th« aircoalum-tin alloy*. Tht#a alloy* have the desirable (karMt«ri»Ue« of high strength, excellent corrosion resistance, and good fabrication qualities.
A Uff# amount of offort ha* boon expended la developing arc-molted, airconium-tln alloya for at# la tho Navy* a submarine thermal reactor. The arc-melting procoa* baa tho advantage over the laductton-melting proceas of introducing lea# contamination Into the melt. However* tho induction-melting proceia teade to produce more homogtneoue alloy* than the arc-melting proceia,
ThU in vet ligation had as tie aim the determination of the mechanical proportion of Induction melted, Bureau of hftoee aponge airconium-tin alloya* Thoae alloy* contain not only the contaminants introduced by thd melting proceae, but alto tbe contaminant* carried in by the aponge air coni urn. A* such, the alloya probably repreaent an ultimate in proceia contamination.
EXPERIMENTAL WORK
Fabrication of the Alloys
The rlrconlum-tln alloya mentioned in thio report were prepared by Induction melting tin and U, 8. Bureau of Mines aponge xircontum. Five- pound heat* were malted in a graphite crueible and poured into a graphite mold to aolldify. The ingot# containing 0* 1* J, 4 and 5 per cent tin were upeet forged and rolled at 1000 C into eheet stock for tenaUe epecimene and into bar atock for impact specimens. The analyses of these ingots are shown In Table l. «r
* 10*
T A ttU l. ANALYSIS or SPONOL lt*COMt)M"TlN ALLOYS J! 1 i 1 1 a u > e 5 s Ugoc a No. Tin Carbon Nitrogen
41) 0 0. 14 0.004 414 1.0 0.10 0.00) 41) 1.0 0.19 0 .0 0 ) 414 4.0 0.11 0.004 417 1.0 0.1S 0.001
The hoi- rolled ih iit •lock v u cleaned by fandbiaeUng, arm cold roiled from i thlckM«« of approximately 0 .1 inch b» I IhlckMH of M ?tf lock. Thl* roiling earned severe edge crocking of oil olioy» except Cho aircooium blank. The cold-rolled alloys were annealed In a straightening proof for one boor at 700 C, oad furnace cooled to room temperature. Tbi» material woo cleaned by surface grinding lo * thickness of 0.06 loch end col into •beet tensile specimens. Hardness dale obtained during the fabrication off Ihlc theft are shown in Table 1.
T i t l t HAAOHtU DATA fOI WONOI UfCOfttUM TW ALLOY I
* n e r A f C a tt Mm - O d d - i n i l p A e a lf th . H fid ata i, M l* 4 f o l k 4 . ftiinnkrf Am o ate # w eight • r ta .ll M tid n sn , War P a n , H ardest!, C ia la M « a . «** *«*•« n< V * 4 ** •“
a g g m 41 m M 0 .0 8 * u s ID « i t M 0 .0 1 0 L a i f ^ U f 14 i a m o.oao 4 . 0 H i n M 10 n 0 .0 1 0 1 . 0 t i ltO 41 u § • 0 . 0 U
T ulls Testing The tensile epeclmene prepared from these ailoya were six inchoe long and 3/4 Inch wide end 0.06 inch thick. Tho reduced section of each tpocimen wot ) inckot long and l/l Inch wide. AU apeclmtna we re cut \
. parallel U the roiling direction. TtiU were run M room temperature end •I 160 C in air* and at 300 C In nn argon atmeephere. Tbe epeed of travel of the Head of the teetmg machine wae O.Oi lath per minute. An «kUM»m^ •t Duplicate toata wore run at each temperature on each alloy. Tht rtitiUa of thaco teete have been averaged and appear in Table 1. Data eelecUd from Table I have boon plotted In Figuree l, 1. and I. Uniform elongation ha a been plotted aa a bettor m ettutc of ductility and working charade rietice than total elongation or reduction of area* YAiua. Ttxuum)mTiwor worn* iv c x m u u 'T W allot e ***1 M l UUlauw tewi AMlydi, TON ■ OfMl n«ak IMIm* W m ptttm , wtlgM Tarapaoaee, Oi K*4*, f t w t C " » 7 - io*H f t COM l a • la. f t aaai « la A T, OM M .4 10 M M M0 11.1 M l t) M 44 MO M i l l II •1 •4 I t 8b * T. 4 M « .t 1 U M MO 10.4 M.O 10 M 40 •00 im •0 ,? 10 01 40 1.0 n IT, wo •0.4 10 M 01 Me W.t ftO.I 0 to 41 M0 18.1 MM 10 M 4T M * t . T. 04.0 01.1 0 IT M M0 N.O 4 1 0 1 14 01 ftoo 81.1 M.O 1ft 14 01 M l i 0. T. n.i M .0 10 10 01 MO 4 1 M.O 0 10 ^ 00 100 •• 57.1 M 1 1 1 * I i i :i I. EFFECT OF TIN on ten sile pr o per ties of spo n g e zirconium at room TEMPERATURE * • • , • * I % » « ' • f FIGURE 2. EFFECT OF TIN ON TENSILE PROPERTIES OF SPONGE ZIRCONIUM AT 260 C A -4 0 M a ! ■ 1 tre p g § JM. i « | • ■ ■ ' i f e r s § f $ : - - Y I p ; M W ...... ; - V II Mi- ’ J f • ' ■ 'l l & i v^SItes :.smm » mm ■ ...... B l i M-iW%iimmmm f . • & ■ 'MW ••lv: $>**# Although the date ere somewhat erratic, there is a definite trend showing that tin strengthens induction melted, Bureau of Mines sponge sirconium. The effect of temperature upon the uniform elongation of the five per cent tin alloy is surprising. The decrease in uniform elonga tion with increasin', temperature is probably related to the strength of the zirconium-tin inter metallic compound present in this alloy. Hot-Hardness Data Diamond pyramid hardnesses of the alloys were obtained at elevated temperatures by means of a vacuum, hot-hardness machine. The vacuum chamber contains a stationary diamond indenter mounted over a hydraulically ope rated i ceramic stage. The indenter, specimen, and stage are heated by open-wire heating coils immediately surrounding them, A thermocouple mounted in the center of the stage records the temperature of the specimen. The specimen which may be about one inch square and 0.1 inch thick can be moved across the stage by an indexing mechanism. Indentations are made by raising the hydraulic stage and specimen into contact with the diamond indenter. The indenter load of 500 grams is applied and measured hydrau lically. A cycle from "no load" to "full load" to "no load" requires about 30 seconds, so that the full load is applied for about 10 seconds. In the course of a test on a single specimen, at least four indentations are made at each temperature up to, and including, 48Z C (900 F). Three indentations are made at each temperature above 48Z C (900 V). The hard ness numbers obtained from the indentations at each temperature are averaged and are shown in Table 4 and Figure 4. These data plotted in Figure 4 show that tin is very effective in main taining the strength of Bureau of Mines sponge sirconium at elevated temperatures. The 5 per cent tin alloy is not quite twice as hard as sponge zirconium at room temperature. However, at temperatures above 600 C, the 5 per cent tin alloy is about 5 times harder than the unalloyed sponge sirconium. If the hardness data shown in Table 4 are plotted against the ultimate strength data given in Table 3, a graph similar to Figure 5 is obtained. This graph shows that, if we allow for experimental errors in both the hardness and tensile tests, there is a linear relation between hardness and ultimate tensile strength. - 16- TA8LE 4. HOT HARDMB8S Of IFONOi ZIRCONIUM-TIN ALLOTS HocHArdnen, Alloy ______DUmond Pyramid Hardncn Number______AoUyili, 304 916 427 483 M l 149 704 760 111 WBi|bt Room CCCCC CC CC pet coot Tomp (400 F) (600F) (800 P) (900 F) (1000 F) (1200 F) (1100 P) (MOO F) (1600 F) 0 Sn 170 91 08 41 19 36 31 16.4 10.8 10.9 2.0 to 170 194 94 74 64 62 IT 117 12.4 10.0 3.0 to 338 140 n o 96 88 94 68 94 28 — 4.0 to SM 164 141 194 114 106 •4 69 21 iMr l . o to 170 219 166 144 148 139 106 83 01 47 Pyramid Hardness Number, kg/m IUE . AOES F NUTO-ETD SPONGE INDUCTION-MELTED OF HARONESS 4. FIGURE ICNU ALY A EEAE TEMPERATURES ELEVATED AT ALLOYS ZIRCONIUM 5 2 ^ * 17 - Sn 5 A-4019 ___ S R iilll iSSfflcWSl • / • 9 y y\ \ / / •X y / s'* s 1 / y • • V / XI S\ / / y i 1 / ¥ * • v "S . i A 4 • ______1 Diamond Pyramid Bordntu Nunbtr, kg /mm* FIGURE 5. RELATION BETWEEN HARDNESS AND TENSILE STRENGTH CF INDUCTION-MELTED SPONGE ZIRCONIUM —TIN ALLOYS UP TO 900 C 4.WiT , smm,1 » - » t l Impact Data The bar stock from each ingot waa annealed for one hoar at 700 C and machined into standard, V-notch, Charpy impact specimens. Speci- mena from each ingot were teated at various temperatures from room temperature to 600 C. The reaulta of these teata are ahown in Table 5. TABLE 8. IMPACT PROPERTIES OP SPONGE ZIRCONIUM-TIN ALLOTS A lloy Energy Absorbed,t Analysis. foot - pound! wight Room 100 200 2S0 900 990 400 600 600 p sr c e n t Temp c C C C C C C C 30 ■ 32 0 So 12 30 36 44 60 60 58 44 42 46 48 46 2 .0 So 17 - 33 34 39 45 52 19 41 44 20 44 46 3 .0 Sn 13 • 33 45 54 16 32 46 16 25 42 4 .0 Sn 10 - 22 31 41 44 in 32 38 38 32 41 o .o on 8 14 17 29 88 30 29 34 Induction melted, Bureau of Mines sponge airconium does not appear to have a aharply defined transition none, and the addition of two or three per cent of tin does not seem to affect its impact behavior* - 20- Four or five per cent tin in an induction-melted alloy of sponge airconium teems to decrease the impact strength of the base material at room temperature and at elevated temperatures. All these alloys appear to have rather low impact strengths at room temperature. Since these alloys were prepared by induction melting in a vacuum furnace, they probably have a low hydrogen contentf so their low impact strength must be caused by other nonmetallic materials. The carbides present in these alloys arc a likely offender. Corrosion Data Small pieces of each alloy were exposed to water at 343 C (650 F) in a stainless steel retort. The sponge airconium blank developed oxide spots and was removed from test after 350 hours. The 2 per cent tin alloy developed a light, flaky oxide and was removed from test after 2180 hours. The 5 per cent tin alloy gained an excessive amount of weight and was removed from test after 2180 hours. The 3 and 4 per cent tin alloys satisfactorily survived 2180 hours in water at 343 C (650 F). These data indicate that tin very definitely improves the corrosion resistance of induction-meltcdi Bureau of Mines sponge airconium. CONCLUSIONS (1) Tin strengthens induction-melted, Bureau of Mines sponge sirconium at both room temperature and elevated tem pera^- tures. The strengthening effect Is progresiive from aero to five per cent tin. (2) The strength of induction-melted. Bureau of Mines sponge sirconium containing no tin falls to half of its room tem perature value at about 230 C. The strength of induction- melted, Bureau of Mines sponge airconium containing five per cent tin falls to half of its room temperature value at about 500 C. (3) Two or three per cent tin does not seem to affect the im pact properties of induction-melted, Bureau of Mines sponge airconium. Four or five per cent tin may decrease the impact strength somewhat. The room-temperature, impact strength of induction-melted, Bureau of Mines sponge sirconium is rather low, \ (4) Tin effectively maintains the hardness of Bureau of Mines sponge zirconium at elevated temperatures, A five per cent tin alloy is about twice as hard as the unalloyed sponge at room temperature, and about five times ae hard as the unalloyed sponge at 700 C, (5) Tin Improves the corrosion resistance of induction* melted, Bureau of Mines sponge zirconium. ADS:WC/et December 31, 1952