冷却速率及杂质元素对锆合金β→α转变组织的影响

Effect of Cooling Rates and Impurities on the Microstructure of β→α Transformation in Zr Alloys

摘要:

锆合金β相冷却组织对于发展高性能燃料包壳具有至关重要的作用。本工作从冷却速率和杂质元素两个影响因素出发，对核反应堆用锆合金β → α转变组织的相关研究进行了综述。锆合金的马氏体转变为无扩散的切变过程，不产生表面浮凸，Ms不随冷却速率变化。成分相同时，随着β冷却速率的增加，锆合金微观结构按如下次序变化：Lenticular组织→Parallel-plate魏氏组织→Basketweave魏氏组织→马氏体。相同冷却速率下，当杂质元素参与形成难溶的第二相时，会促进Basketweave组织的形成，而当这些元素提高β转变温度时，则倾向于促进Parallel-plate组织的形成

Abstract:

This paper presents a comprehensive review about the effect of cooling rates and impurities on the microstructure of zirconium alloys during β→α transformation with the expectation to facilitate the development of high-performance zirconium-based cladding materials. For zirconium alloys, the diffusionless Martensitic transformation does not produce a surface rumpling after quenching the pre-polished specimens. The Ms temperature keeps independent of β quenching rates. When alloy composition is fixed, increasing of cooling rate causes microstructural change in the following sequence: lenticular α→Parallel plate α→Basketweave α→Martensitic α'. The impurities which can form insoluble second phase particles in β phase will promote the formation of Basketweave Widmanstatten structures. However, the impurities that might increase β phase transformation temperature will lead to more Parallel-plate Widmanstatten structures