Ti-Mo合金氢化物原位脱氢的相变研究  

The Phase Transformation of Ti-Mo Alloy Hydrides in Dehydrogenation In-situ X-ray Powder Diffraction

作　　者：苑学众[1] 郭秀梅[2] 吴尔冬[3] 王苏程[3] 

机构地区：[1]沈阳建筑大学理学院,辽宁沈阳110168 [2]北京有色金属研究总院,北京100088 [3]中国科学院金属研究所沈阳材料科学国家实验室,辽宁沈阳110016

出　　处：《沈阳建筑大学学报（自然科学版）》2013年第1期174-180,共7页Journal of Shenyang Jianzhu University：Natural Science

基　　金：国家自然科学基金项目(11079043)

摘　　要：目的研究Ti-Mo合金氢化物在原位退火中相变行为,分析Ti-Mo合金氢化物原位退火中的结构变化.方法利用X射线原位衍射对不同成分的Ti-Mo合金的氢化物在退火过程中的相变用Rietveld法进行了分析.对晶格参数、微观应变在退火过程中的变化用Rietveld法程序进行了计算.对部分样品进行了透射电镜分析.结果 Ti-Mo合金饱和充氢后形成面心立方δ相氢化物,在升温过程中转变为体心立方β相固溶体.随着温度升高,δ相与β相的晶粒尺寸和微观应变基本上都经历逐渐增大然后又变小的过程.在相转化的同时,δ相与β相的晶格参数基本随温度的升高而减小.衍射峰形和峰位存在各向异性展宽和位移.结论用X射线原位衍射结合Rietveld法得到了Ti-Mo合金氢化物的相变信息.δ相氢化物存在广泛的位错和层错(孪晶).一些样品在退火中同时出现两个不同晶格参数的β相.The behaviors of phase transformation of Ti-Mo alloy hydrides are studied.The structure changes of the hydrides during the in-situ annealing are analyzed.The in-situ X-ray powder diffraction measurements and Rietveld refinements have been used to study the dehydrogenation of seven hydrides of Ti-Mo alloys during annealing.The lattice parameters and r.m.s strains during annealing are calculated by computer program LHPM.Some samples are analyzed by means of TEM.The fully hydrogenated Ti-Mo alloys have single fcc δ-phase.During annealing,the bcc β-phase solid solutions are precipitated and grown from the δ-phase.Along with increasing temperatures,the developments of the r.m.s strains of the two phases show a trend of undergoing a small-large-small sequence.In general,both lattices of δ and β phases decrease with the increase of Mo contents and the rising temperatures.The diffraction patterns reveal anisotropic line broadening and peak displacements.The observed phenomena during annealing have been explained and discussed.There are high density dislocations,stacking faults and twins in the δ-phase hydrides.During annealing,double β phases with different lattice parameters are found in some hydrides.

关 键 词：Ti-Mo合金氢化物 原位X射线衍射 Rietveld法 位错 层错 

分 类 号：O723[理学—晶体学]