High-Dense Shock Reactive Processing of Molybdenum and Titanium Silicides

钼硅化物和钛硅化物的高密度冲击反应加工

基本信息

批准号：
07555216
负责人：
AIZAWA Tatsuhiko
金额：
$ 7.36万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

Shock reactive synthesis can be classified into two categories : 1) Shock Assisted Reaction and 2) Shock Induced Reaction. In the former, since thermal transients and residual heating often overwhelm the reaction mechanism during shock loading, the shock reactions are forced to be terminated at the intermediate steps and the liquid phase of reactants should play a role in the shock reaction mechanism. In the latter, effect of shock pressure on the shock reactive reactions reveals the shock reaction mechanism, resulting in the formation of non-equilibrium phase and exotic materials. Starting from the element powder mixture, every shock reactive synthesis becomes a shock assisted reaction, so that high pressure beyond 20 GPa should be needed to improve the shock reactivity only for partial reaction. On the other hand, starting from the pretreated powders by mechanical alloying, those MA precursors can be fully reacted into intermetallic compound with or without non-equilibrium phase materials. In the present paper, both the bulk mechanical alloying and the modified milling-type mechanical alloying were employed to vary the premixing level in the pretreatment process for investigation of the pretratment effects on the shock induced reactions. Ni-Al, Ti-Al, Mo-Si, Ti-Si and Nb-Si systems were used for target material for experimental demonstration to verify that the shock reasctive synthesis from pretreated powders should yield dense fully-reacted intermetallic compounds for p < 15 GPa. In the experiments, the uniaxilly compressed compacts of pretreated powders were employed as a sample of shock recovery tests for various shock prssure. With comparison to thermally-ignited and mechanically-induced SHS and shock reactive synthesis from elemental powder mixture, reaction mechanism of shock induced reactions was considered to make advancement in shock chemistry for processing of refractory metal aluminides and silicides.

冲击反应合成可分为两类：1）冲击辅助反应和2）冲击诱导反应。在前者中，由于在冲击加载过程中热瞬变和余热常常压倒反应机制，因此冲击反应在中间步骤被迫终止，反应物的液相应在冲击反应机制中发挥作用。在后者中，冲击压力对冲击反应反应的影响揭示了冲击反应机理，导致非平衡相和奇异材料的形成。从元素粉末混合物开始，每次冲击反应合成都变成冲击辅助反应，因此仅对于部分反应就需要20 GPa以上的高压来提高冲击反应性。另一方面，从机械合金化预处理的粉末开始，这些MA前驱体可以在有或没有非平衡相材料的情况下充分反应成金属间化合物。在本文中，采用块体机械合金化和改进的铣削型机械合金化来改变预处理过程中的预混合水平，以研究预处理对冲击诱发反应的影响。使用 Ni-Al、Ti-Al、Mo-Si、Ti-Si 和 Nb-Si 系统作为靶材料进行实验演示，以验证预处理粉末的冲击反应合成应产生 p < 15 的致密完全反应金属间化合物GPa。在实验中，采用预处理粉末的单轴压缩压坯作为各种冲击压力的冲击恢复测试的样品。与热点燃和机械诱导的SHS以及元素粉末混合物的冲击反应合成相比，冲击诱导反应的反应机理被认为在难熔金属铝化物和硅化物加工的冲击化学方面取得了进步。