纳米材料的马氏体相变

The nanostructured Fe-Ni alloys, Co metal and ZrO2-based compound ceramics have been produced with magnetic sputtering, mechanical alloying and co-precipitatin methods respectively. Both the micro structure and the transformation in these mateirials were characterized by TEM and X-ray diffraction. Meanwhile, the tructure stability and nucleation barrier for transformation were calculated and the critical size for stability of high temperature structure at room temperature with different excess volume were predicted based on our two different theoretical models. The results are consistant with experimental phenomena that the occurrence of matensitic transformation in Co is easier than that in Fe-Ni or in ZrO2. The auto-catalystical effect for martensitic transformation in nanosized materials is weaker ignificantly than in bulk materials. Thermodynamics was employed to explain the reason that widening behavior of compositional range of both fcc and fcc structures in Fe-Ni nanosized crystal, also in agreement with our experimental results

研究新兴纳米材料的马氏体相变特性，借助纳米晶粒材料马氏体相变的研究为马氏体相变的尺寸效应及形核机制提供新的有力论据，探讨纳米级材料马氏体相变的热力学、动力学和形核机制，建立纳米材料马氏体相变温度Ms的完整热力学计算方法。