充氢对多孔TC4钛合金室温组织的影响

Influence of Hydrogenation on Room Temperature Microstructure of Porous TC4 Alloy

利用管式氢处理炉,采取固态气相渗氢法对多孔TC4钛合金进行充氢试验。采用光学显微镜、X射线衍射和扫描电镜等手段,研究相对密度、充氢温度和充氢时间对多孔TC4钛合金的相组成及微观组织的影响。研究结果表明,随氢质量分数的增加,多孔TC4钛合金的α相逐渐减少,β相逐渐增多,并形成δ氢化物;充氢温度达到某一临界温度时,一定量的氢可诱发多孔TC4钛合金的马氏体转变,生成α″马氏体;充氢后多孔TC4钛合金由原始等轴组织转变为针状和片层状的细小组织,当充氢温度较高氢质量分数较高时,出现片层状α″马氏体组织,当充氢温度较低氢质量分数较高时则出现网篮状α片层组织。充氢多孔TC4钛合金的微观组织与氢质量分数相当的TC4钛合金粉末相比整体要细小。

Hydrogenation experiments in porous TC4 alloys are investigated through gas-solid hydrogenated method by using a tubular hydrogen treatment furnace. The influences of relative density, hydrogenation temperature and time on phase composition and microstructure evolution are investigated by means of optical microscope （O P）, X-ray diffraction （XRD） and scanning electron microscope （SEM）. The result shows that the α phase decreases and β phase increases with the increase of hydrogen content, meanwhile, some δ hydrides are formed. At a certain critical temperature, a certain amount of hydrogen will induce martensite phase transformation, which results in the formation of martensite a＂. After hydrogenation, the original equiaxed microstructure in porous TC4 alloy transforms into acicular and lamellar structure. With higher hydrogen content, laminar martensite a＂ phase is observed when the temperature is higher, while the basket-weave a phase is shown when the temperature is lower. The microstructure of porous TC4 alloy is finer than the titanium alloy powder with the similar hydrogen content.