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利用光学显微镜(OM)、X射线衍射(XRD)和透射电子显微镜(TEM)研究TC21合金吸氢与放氢后的组织演变和相的转变。研究表明:吸氢后,α和β相的衍射峰向低的2θ角方向偏移,说明氢原子固溶于合金中,使其晶体结构发生膨胀;TC21合金的组织也发生明显的变化。吸氢后,α相和β相的明暗对比度发生变化,原白色α相(金相组织)转变为黑色,而且黑色组织中分布有取向不同且平行排列的片状组织。XRD分析和TEM观察发现,在合金中有氢化物和α′马氏体生成,还在相内和相间存在大量的孪晶和少量的粒子。这意味着氢导致α和β相中合金元素的再分配。放氢后,TC21合金的组织与吸氢前合金的组织相似,只包括α相和β相。
The microstructure evolution and phase transition of TC21 alloy after hydrogen and hydrogen evolution were studied by OM, XRD and TEM. The results show that the diffraction peaks of α and β phase shift to the low 2θ angle after hydrogen absorption, indicating that the hydrogen atoms are dissolved in the alloy and the crystal structure is swollen. The microstructure of TC21 alloy also changes obviously. After hydrogen absorption, the contrast between the α and β phases changed. The original white α phase (microstructure) changed to black, and the black tissue was distributed with different parallel oriented sheet-like structures. XRD analysis and TEM observation showed that there are hydride and α ’martensite in the alloy, and a large amount of twins and a few particles exist in and between the phases. This means that hydrogen causes redistribution of alloying elements in the [alpha] and [beta] phases. After hydrogen releasing, the microstructure of TC21 alloy is similar to that of the hydrogen absorbing alloy, including only α phase and β phase.