(1. 重庆大学 材料与科学工程学院 教育部轻合金材料国际联合实验室，重庆 400044；
2. 燕山大学 亚稳材料制备技术与科学国家重点实验室，秦皇岛 066004)
摘 要: 结合EBSD和XRD，系统地研究了β-51.1Zr40.2Ti4.5Al4.2V合金在炉冷过程中3种α相(αGB、αWGB和αWI)的形核机制以及α含量对合金性能的影响。结果表明：炉冷过程中，在原β界面处具有{0001}面平行于相邻β晶粒共有{110}面取向特征的α相(αGB)会优先形核；αWGB主要以界面不稳定形核为主，通过继承αGB的取向并向原β晶内生长，从而在晶界附近形成平行板条区；为了协调相变过程中产生的形状应变，αWI通过自协作机制产生三变体团簇，且形成三变体团簇的变体之间相互满足60°/ 取向关系；随着炉冷后保温温度的降低，α相的相对含量增加，合金的硬度增大，且硬度和α相的相对含量存在一定的线性关系。
关键字: 取向关系；形核机制；自协作机制；EBSD
（1. International Joint Laboratory for Light Alloys, Ministry of Education, College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China）
Abstract:The nucleation mechanism of three kinds of α phase (αGB, αWGB and αWI) in furnace-cooling β-51.1Zr40.2Ti4.5Al4.2V alloy and the effect of the relative volume fraction of α and β phases on mechanical properties were investigated systematically by EBSD and XRD. The results show that the αGB with {0001} pole parallel to the common {110} pole of adjacent β grains will present preferred nucleation at β grain boundary. The major nucleation mechanism of αWGB is interface instability nucleation, therefore, αWGB grains nucleate and grow into the interior of prior β grains by inheriting the orientation of αGB. In order to coordinate the strain energy formed during the β→α transformation, αWI develops three-variant cluster by so-called self-accommodation mechanism, the three variants are related to each other by an angle/axis pair 60°/ . With the decrease of furnace-cooling temperature, the relative volume fraction of α phase increases, resulting in the increasement of hardness. There is a linear relationship between hardness and the relative volume fraction of α phase.
Key words: orientation relationship; nucleation mechanism; self-accommodation; EBSD
