Ti6Al4V合金渗氢氢化组织及氢脆机制的研究  

Investigation on the Microstructures and Hydrogen Embrittlement Mechanism of Hydrogenated Ti6Al4V

作　　者：苏彦庆[1] 骆良顺[1] 郭景杰[1] 贾均[1] 傅恒志[1] 

机构地区：[1]哈尔滨工业大学金属精密热加工国防科技重点实验室,黑龙江哈尔滨150001

出　　处：《稀有金属材料与工程》2005年第4期526-530,共5页Rare Metal Materials and Engineering

基　　金：黑龙江省杰出青年科学基金资助项目;"973"资助项目(G2000067201-2)

摘　　要：利用XRD,TEM研究了渗氢后Ti6Al4V合金的组织变化。在渗氢0.302%(质量分数,下同)及0.490%的试样中发现了面心立方的氢化物δ和大量的斜方结构的马氏体α"。提出了1种基于扩散的由βH共析转变生成α及fcc结构的片状氢化物δ的机制,并指出氢的引入可能诱发马氏体转变。在室温拉伸试验中发现在氢含量不高于0.102%时不发生氢致脆化。氢化物δ和马氏体α"在Ti6Al4V合金的氢脆中起主要作用,氢化物δ既有利于裂纹的萌生又有利于裂纹的扩展,而马氏体α"对裂纹的扩展具有重要的作用,二者共同促进了Ti6Al4V合金的室温高氢含量氢脆。The microstructure of Ti6Al4V alloy after hydrogenation has been investigated by XRD and TEM. It is shown that there are δ titanium hydride (fcc structure, a=0.444 nm) plates precipitated in the specimens containing 0.302wt% and 0.490wt% hydrogen. Simultaneously, mass tetragonal martensite α' has been found in the specimens as well as δ hydride. One eutectoid transformation mechanism from β(H) to δ hydride and α-Ti is presented, based on diffusion transformation theory. The martensite transformation induced by hydrogen has also been discussed. Hydrogen-induced embrittlement did not appear until the hydrogen content exceeded 0.102wt%. δ titanium hydride and martensite α' has the leading effects of hydrogen embrittlement of Ti6Al4V alloy at room temperature, and δ hydride plates distributed along grain boundaries make for the germination and propagation of crack, while the tetragonal martensite α' has positive effect on the propagation of crack. As a result, these two phases jointly caused the hydrogen embrittlement of Ti6Al4V alloy at room temperature.

关 键 词：TI6AL4V 渗氢 氢化物 氢脆 断裂机制 

分 类 号：TG156.8[金属学及工艺—热处理]