| Budget Amount *help |
¥11,500,000 (Direct Cost: ¥11,500,000)
Fiscal Year 1996: ¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1995: ¥9,000,000 (Direct Cost: ¥9,000,000)
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| Research Abstract |
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.
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