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用热压法制备Ti/Al扩散偶,并在525,550,575,600℃进行热处理。结果表明:当Al未完全消耗时,TiAl3是Ti/Al界面处唯一的产物,TiAl3向Al箔一侧长大,Ti箔中没有检测到Al原子的存在。从固溶体的溶解度极限,Al、Ti和TiAl3的晶格失配度,以及新相形成所增加的界面能3个方面解释TiAl3的首先生成。Ti在Al中的溶解度极限很小,Al(Ti)固溶体很容易生成,以及Al、Ti和TiAl3的密排面错配度很小,促使TiAl3优先形核。在所有Ti-Al化合物中,形成TiAl3所增加的界面能最少,有利于TiAl3优先形核长大。由于动力学的不稳定性,其他Ti-Al化合物的生成与长大受到抑制。
Ti / Al diffusion couples were prepared by hot pressing and heat treated at 525, 550, 575, 600 ° C. The results show that when Al is not completely consumed, TiAl3 is the only product at Ti / Al interface. TiAl3 grows to one side of Al foil and no Al atoms are detected in Ti foil. The first generation of TiAl3 is explained from three aspects: solubility limit of solid solution, lattice mismatch of Al, Ti and TiAl3, and interfacial energy increased by new phase formation. The solubility limit of Ti in Al is very small, the Al (Ti) solid solution is easy to be formed, and the misclassification degree of the dense surfaces of Al, Ti and TiAl3 is very small, prompting the preferential nucleation of TiAl3. In all Ti-Al compounds, the formation of TiAl3 increases the minimum interfacial energy conducive to preferential nucleation and growth of TiAl3. Due to the kinetic instability, the formation and growth of other Ti-Al compounds are inhibited.