摘要
采用四点接线电阻法测定了外加拉应力作用下燃烧合成Ti50Ni(at%)形状记忆合金马氏体相变点Ms的变化,并从宏观热力学和微观相变动力学两方面综合分析外力对TiNi合金马氏体相变点Ms的影响。在再结晶退火TiNi合金中,马氏体/母相界面间保持良好共格关系,外力的宏观热力学作用可使Ms上升,而从微观动力学方面看,外力可破坏界面的共格性,使界面可动性及Ms下降,两者作用相互抵消的结果导致Ms随外力增加变化不大;而在冷加工后回复退火TiNi中仍存在大量冷加工位错,其马氏体/母相界面间的共格性已遭到这些位错的明显破坏,外力通过微观相变动力学作用使Ms下降的趋势已很小,而主要是通过热力学作用使Ms值明显上升。
The effect of an applied stress on martensitic transformation temperature, Ms, of Ti-50at% Ni alloy prepared by combustion synthesis has been studied and interpreted in terms of the macrothermodynamics and microkinetics associated with martensitic transformation. For the full-recrystallized TiNi alloy in which the perfectly coherent interfaces between martensite and parent phase do exit, the applied stress would increase Ms by its macrothermodynamic effect, also it would lower Ms by its microdynamic effect because the applied stress can make the interfaces gradually lose coherence and reduce the movability of the interfaces. These two opposite effects act together and result in no evident change trend of Ms with the applied stress increasing. However, in TiNi alloy recovered after cold work, so many residual cold-working dislocations have made the coherence of the interfaces drop distinctly that the microkinetic effect of the applied stress is very small, thus the Ms can go up with the increasement of the applied stress and its macrothermodynamic effect.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
1998年第3期169-172,共4页
Rare Metal Materials and Engineering