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Dispersion Hardening and Super-Plastic Titanium Alloys Prepared by Mechanical alloying, and Their Deformation Modes

机械合金化制备弥散硬化超塑性钛合金及其变形模式

基本信息

批准号：
01550553
负责人：
HIDA Moritaka
金额：
$ 1.73万
依托单位：
Okayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1991
项目状态：
已结题

项目摘要

The following results obtained for the past three years are very important to clarify the mechanochemical potentials about mechanical alloying(MA)and the limits of the application to materials engineering.1)As long as the ball milling energy is high enough, solid solution alloy is completely performed even for the alloy system being difficult to prepare by melt method.2)The fatal defect of MA is contamination from the ball mill made of steel. The titanium ball mill is used to prevent the contamination. But the potential energy of MA drops so as to be proportional to the weight of the balls.3)As titanium is chemically active, the 5N and 4N purity carrier gases, Ar, N_2 etc., should be'purified with sponge titanium heated above 523K in order to prevent the surface oxidation of powder. The deoxidation of Ar gas promotes sticking of MA powder to the ball mill. The deoxidized N_2 has a potential of solving 8mass%N as nitride TiN in Ti matrix for 144ks MA with Ti ball mill. TiN is dissociated to Ti-N solid solution at high pressure.4)When the mixed powder of Ti-9.5V-2.5Mo-3AI is mechanically alloyed for 432ks with Ti ball mill, the alloy system becomes to beta solid solution powder expected to be super-plastic in bulk sample.5)The consolidation of some kinds of MA powder is tried by HIP treatment(1270K, 100MPa). Failures of HIP sample made of MA powder of Ti-Mo, Ti-V-Mo-Al, Ti-N take place during cooling to 300K and reducing pressure to O. lMPa. The after effect of MA and HIP treatments cause drastically decreasing the ductility of the consolidated samples.6)The engineering application of MA depends on the success of the consolidation of powders which remains ductility as the bulk sample.

近3年来的研究结果对阐明机械合金化的机械化学势及其在材料工程中应用的局限性具有重要意义：1）对于熔融法难以制备的合金体系，只要球磨能量足够高，固溶合金化也能完全进行; 2）机械合金化的致命缺陷是钢制球磨机的污染。采用钛合金球磨机，防止污染。3）由于钛的化学活性，采用5 N和4 N纯度的载气Ar、N_2等，为防止粉末表面氧化，应采用523 K以上加热的海绵钛进行提纯。氩气的脱氧作用促进了MA粉末与球磨机的粘结。在144 ksMA中，还原后的N_2具有将8mass%N作为TiN氮化物固溶在Ti基体中的潜力。Ti-9.5V-2.5Mo-3Al混合粉末经球磨432 ks后，合金体系转变为β固溶体粉末，在块体试样中具有超塑性。用Ti-Mo、Ti-V-Mo-Al、Ti-N的MA粉末制备的热等静压试样在冷却至300 K和减压至0. 1MPa。机械合金化和热等静压处理的后效使试样的塑性急剧下降。6）机械合金化的工程应用取决于能否成功地将粉末固结成具有整体塑性的试样。