热力耦合作用下钛合金动态相变行为研究进展

变形和相变是钛合金材料研究的两大主题。钛合金通常需要进行一系列复杂的热机械处理,以获得与服役性能相对应的微观组织,其热变形行为是典型的热力耦合作用过程,变形和相变可能同时发生,并相互影响,是目前的研究热点之一。然而,由于热变形过程中不可避免地存在动态回复/再结晶、组织破碎/球化、大量变形缺陷、变形织构以及应力诱发相变等演化行为,加上热力耦合作用下相变动力学特征和变体选择晶体学机制的改变,直接导致钛合金热变形过程中的动态相变行为变得极为复杂,深入揭示其演变规律也变得相当困难。本文针对钛合金热变形过程中的动态相变行为,总结了钛合金变形及相变的主要特征和规律,重点从析出相形貌特征、变体选择机制和相变动力学特征三个方面介绍了钛合金热力耦合作用下动态相变规律的研究进展,并对其研究发展趋势进行了总结和展望。

Research progress of dynamic phase transformation behavior of titanium alloy under thermo-mechanical coupling process

Deformation and phase transformation are two major topics in the study of titanium alloy materials.Titanium alloys usually require a series of complex thermo-mechanical treatments to obtain a microstructure corresponding to service performance.Its hot deformation behavior is a typical thermo-mechanical coupling process.Deformation and phase transformation may occur simultaneously and affect each other.It is one of the current research hotspots.However,due to the inevitable existence of dynamic recovery/recrystallization,microstructure fragmentation/spheroidization,a large number of deformation defects,deformation texture,and stress-induced phase transformation during hot deformation,coupled with the changes of the phase transformation kinetics characteristics and the crystallographic mechanism of the variant selection under thermo-mechanical coupling,directly leads to the extremely complicated dynamic phase transformation behavior of the titanium alloy during the hot deformation process,and it becomes quite difficult to reveal its evolution law in depth.This paper summarizes the main characteristics and laws of titanium alloy deformation and phase transformation in view of the dynamic phase transformation behavior of titanium alloy during hot deformation,mainly introduces the research progress of the dynamic phase transformation of the titanium alloy under the thermomechanical coupling from the three aspects of precipitation phase morphology characteristics,variant selection mechanism and phase transformation kinetics characteristics,and summarizes and prospects its research and development trend.