The real hydrogenation contents were controlled in the range from 0 to 0.69% (mass fraction) by adding TiH2 powders to the raw powders, and the effects of real hydrogenation contents on microstructure evolution and phase composition, morphology and distribution of sintering Ti-6Al-4V alloys were comprehensively investigated. Means of OM, SEM, EDS, XRD and EBSD were used for the exploration and characterization. The results are as the follows: 1) The time for microstructure reaching the near-equilibrium-state reduces from 3 h to 2 h at hydrogenation content of 0.12%. 2) With hydrogenation content increases to 0.69% gradually, the volume fraction of α phase reduces from 82.44% to 15.22% and the volume fraction of β phase increases from 3.59% to 50.77%. Meanwhile, coarse lamellar α phase transforms to fine lamellar α phase distributing around β phase discontinuously, and thin strip β phase distributing between α phases discontinuously transforms to plate β phase. 3) The volume fraction of HCP α′ martensite increases from about 8% to about 25% with the increase of hydrogenation content, which distributes in α phase locally and intensively; Acicular δ hydride generates at 0.54% hydrogenation content, which distributes in α and β phases and between the two phases. Meanwhile, the volume fraction of HCP α' martensite reduces to about 8% again. 4) Though the volume fraction of orthorhombic α" martensite increases with the increase of hydrogenation content, it only reaches about 5% and distributes in α phase with small equiaxed shape. 5) The hydrogenation content can also effectively affect the microstructure composition, (α+β) lamellar beam and grain morphology. Finally, the microstructure evolution mechanism of hydrogenated sintering Ti-6Al-4V alloys was analyzed and discussed on the basis of experimental results.%通过在原料粉末中配置TiH2粉末的方法将烧结Ti-6Al-4V合金的实际置氢量控制在0~0.69%,系统研究了置氢量对显微组织演变、相构成、形态与分布的影响规律,并借助OM、SEM、EDS、XRD和EBSD开展探究与表征.结果表明:1) 置入0.12%的氢可以使合金获得近平衡态显微组织的烧结时间从3 h减少为2 h.2) 当置氢量逐步增加到0.69%时,α相含量从82.44%急剧减少至15.22%,而β相含量从3.59%增加到50.77%,同时α相的形态从粗大片状转变为断续分布于β相周围的细片状,β相的形态则从断续分布于α相间的细条状转变为板块状.3) 随着置氢量的提高,HCPα'马氏体的含量从8%左右增加到约25%,并呈局部集中状分布在α相内;置氢量为0.54%时,针状δ氢化物开始生成,分布在α和β相内及两相之间,此时α'的含量再次降低至8%左右.4) 斜方结构马氏体α"的含量也随着置氢量的提高而增加,但是当α"含量达到5%左右后便维持不变,呈细小等轴状分布于α相内.5) 置氢量对合金中显微组织构成、α+β片层束及晶粒形态能够产生显著影响.最后,根据实验结果对置氢烧结Ti-6Al-4V合金显微组织的演变机理开展了分析与讨论.
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