. . * * * . . < - I OF L ORNL P 1506 07 . on : Ø XX ទី ទី ៥ ៩ 9:13 MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS -1963 NU 1 1 2 - . TE ny E 4: . - LEGAL NOTICE This report was prepared as an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty or representa- tion, expressed or implied, with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information, appa- ratus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of, or for damages resulting from the use of any information, apparatus, method, or process disclosed in this report. As used in the above, “person acting on behalf of the Commission” includes any em- ployee or contractor of the Commission, or employee of such contractor, to the extent that such employee or contractor of the Commission, or employee of such contractor prepares, disseminates, or provides access to, any information pursuant to his employ- ment or contract with the Commission, or his employment with such contractor. mr.az trwanie * - renewens. iene =-4 12 •r. Ornip 1506 1 - - - Summary for presentation at the 1965 Winter Meeting of the American Nuclear Society, Washington, D. C., November 15-18, 1965. - ... SEⓇIES .- . • ORNL - AEC - OFFICIAL . Conf.65/101-19 ORNI - AC - ORBICIAL LOW-TEMPERATURE DUCTILITY AND STRENGTH OF the VAPOR-DEPOSITED TUNGSTEN **.-5.kn MASTER * A. C. Schaffhauser** Metals and Ceramics Division Oak Ridge National Laboratory Oak Ridge, Tennessee -- *. .-- -- --- Vapor-deposited tungsten has many unique characteristics that are useful in nuclear applications. Intricate parts of very high purity -- may be easily deposited in their final form. The grain structure is --- --------- highly oriented - a feature which is particularly useful for thermionic ---- applications - and is stable to temperatures as high as 2500°C. 2 -- *** However, a major limitation of this material is its low-temperature brittleness. Very little data are available on the low-temperature properties of vapor-deposited tungsten, especially the effect of RELEASED FOR WITNOTICEMENT IN NUCLEAR SCIENCE ASSTRACT'S heat treatment and high-temperature exposure on ductility and strength. į The ductility of vapor-deposited tungsten in terms of the ductile-to-brittle transition temperature*** for a series of l-hr vacuum anneals is compared with comercial tungsten sheet prepared by the powder-metallurgy route in Fig. 1. Vapor-deposited tungsten sheet material was obtained by hydrogen reduction of WF6 at 600 °C 'within a square tube mandrel.? · *Research sponsored by the U. S. Atomic Energy Commission under contract with the Union Carbide Corporation. **Sponsor: J. E. Cunningham. ORNI - AEC - OFFICIAL *** Lowest test temperature at which a 90-degree bend could be obtained without cracking. -LEGAL NOTICE - ORNI - AEC - OFFICIAL The raport mw propered M oo a Cover p owon with Matthee to our Hain, nor de Comedian, www porno nothing an d unleston A. Mam wywirunty or mo ntador, aprender laptele mai maret to the more rrey, completamme, e welaws of the weather conten t or two of my hormationen, wenn, wded, * poco declown moment name privately owned rights of - B. Assumes say Habilities with respect to the nao et, er for damages resulting from the w of warnedim, ementum, method, moon koott umarte As wood to the move, sporen acting a hotel a Candino o modelo de ne ployee or contracter of the Commission, or ompleyoo at much contractor, to the datant that wel pleyna at omtractor of the Center, plays a wela waracter personen doornimam, pa mount, mag wormat per Melayu treda wa the countrie, « Mouplage while we continue. • ORNI -AEC - OFFICIAL OINI - AC - ORSICIAL The large decrease in transition temperature on annealing vapor- deposited tungsten at temperatures between 1000 and 1800°C is primarily due to stress relief; there was no observable change in grain structure or purity. Some grain coarsening was evident after annealing at 2200°C while significant grain growth and some interstitial impurity contami- nation was observed after annealing at 2500°C. These latter effects could account for the sharp increase in transition temperature. The higher initial purity of the vapor-deposited material is most likely responsible for its lower transition temperature for annealing tempera- tures of 1300 to 2200°C as compared to the recrystallized powder- metallurgy tungsten. The low-temperature yield strengths of vapor-deposited and powder-metallurgy tungsten bend specimens after heat treatment are shown in Fig. 2. The yield strength of the as-received (stress relieved 5 min at 1150°C) powder-metallurgy tungsten is much greater than stress-relieved, vapor-deposited tungsten; however, after an 1800°C anneal the strengths are comparable and after exposure at 2500°C the vapor-deposited material is stronger due to the greater stability of the grain structure! References References 1. A. F. keinberg, et al., Vapor-deposited Tungsten, NASA CR-54266 (Oct. 6, 1964). 2. F. H. Patterson, et al., "Thermochemical Deposition of Tungsten," Metals and Ceramics Div. Ann. Progr. Rept. June 30, 1965, ORNL-3870, Chapter 4. ORNI - AEC - OFFICIAL ORNI - AEC - OFFICIAL ITTTTTTTTTTT ORNI - ACC - OFFICIAL BRM Enf-origini dia tienda Fig. 1. Effect of Heat Treatment on the Transition Tempe of Vapor-Deposited and Powder-Metallurgy Tungsten. TIN MCV CU 12 . ISIVAIOANCEAOSITE MILETOWDERIE, 2222221 SISI TIC PODERARSIZ 224CTETTONOTTAWAZ 0227diInnoRTAMENT EXCLU! ORNI - AEC - OFFICIAL 84144 - 46€ -ffleliny MENLJINATURE IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII , 1. . . . M Fig. 2. Yield Strength of Heat Treated Vapor-Deposited and Powder-Metallurgy Tungsten. DITT UILO Wart . TÖITTUIR AT VOCOT EUGENE DIEliuliu MAOC IN U. , lynchi U70527 Rok 1.TALKALMALAIZAL TUTTURTĀRS EINLATY InoworTMETALLURGY CHRIATICI 72TATII 3000 Y . METHING Oitic3EN Chairs bürcn :0 X 10 PER INCH NO. 3•:1:10 P ri!!.?. "Sijis 1 END DATE FILMED 10/ 20 / 65 IN ti