钛合金中马氏体相变的变体选择和组织特征研究进展

Research Progress on Variant Selection and Microstructural Characteristics of Martensitic Transformation of Titanium Alloys

摘要:

在钛合金实际生产和加工中，由于各种因素的存在，马氏体相变过程中往往会发生变体选择。变体择优取向行为使得组织中α′/α″晶体取向偏离了理论上的等概率分布，进而影响材料的各向异性和力学性能。研究表明，淬火β→α′相变有弱变体选择特征，应力诱发β→α″相变常常出现强变体选择效应且总是倾向于适应最大外应力的方向发生。与此同时，α′/α″马氏体微观组织中经常观察到多个变体聚集在一起形成三角形、V形、Z型、梯形和平行簇等特殊的特征形貌，这种自调节结构的出现是引起变体选择效应的重要原因之一。本文系统阐述了马氏体相变的特点和形成机制，揭示和归纳了变体选择的本质以及影响变体选择的因素；结合马氏体现象学理论、变体间界面统计等方法，解析和总结了伴随变体选择效应发生的马氏体自调节组织形成机制以及界面分布规律，最后指出了目前存在的问题和挑战以及今后的研究重点。

Abstract:

In the practical production and processing of titanium alloys, variant selection frequently occurs during martensitic transformation due to various influencing factors. This preferential behavior causes the crystallographic orientation distribution of α′/α″ phases to deviate from theoretical equiprobability, consequently affecting material anisotropy and mechanical properties. Studies reveal that quenching-induced β→α′ transformation exhibits weak variant selection characteristics. In contrast, stress-induced β→α″ transformation often demonstrates strong variant selection effects with a consistent preference for orientations accommodating maximum external stress. Simultaneously, characteristic self-accommodating morphologies are commonly observed in α′/α″ martensitic microstructures, including triangular, V-shaped, Z-shaped, trapezoidal, and parallel clusters formed by aggregated variants. The emergence of these self-accommodating clusters is one of the critical mechanisms underlying variant selection effects. This paper systematically elaborates on the characteristics and formation mechanisms of martensitic transformation and elucidates the intrinsic nature and influencing factors of variant selection. By integrating the phenomenological theory of martensite and statistical analysis of inter-variant interfaces, the formation mechanisms of self-accommodating microstructures and interface distribution associated with variant selection effects are analyzed comprehensively. Finally, current challenges and future research priorities in this field are identified.