Mechanisms of heat treatment and ductility improvement of high-oxygen Ti-6Al-4V alloy fabricated by metal injection molding
Mechanisms of heat treatment and ductility improvement of high-oxygen Ti-6Al-4V alloy fabricated by metal injection molding
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DOI：
10.1016/j.msea.2022.142924
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发表时间：
2022-03-09
期刊：
影响因子：
6.4
通讯作者：
Ye, Shulong
中科院分区：
文献类型：
--
作者：
Bian, Tieyuan;Ding, Chao;Ye, Shulong
采用金属注射成型的方法制备了含氧4000ppm的Ti-6Al-4V合金样品。样品进行热处理，其中样品在β横断面以下进行固溶处理，随后水淬。拉伸试验表明，热处理后合金的塑性伸长率由1.0提高到3.2%。热处理过程中组织演变的研究表明，存在于烧结试样的β层状组织中对其塑性有害的针状α相被淬火抑制并有效地从热处理试样中消除。此外，在固溶处理中，合金分裂为初级α相和β相。在水淬过程中，β相转变为次生α相和β相的片层结构，其延展性得到提高。结果表明，热处理试样的延性提高是由于延性层状组织的塑性变形和刚性初级α相的协同位移。
Ti-6Al-4V alloy samples with 4000 ppm oxygen are fabricated by metal injection molding. The samples are subjected to a heat-treatment, in which the samples are solution-treated below the beta transus and subsequently water-quenched. The tensile tests on the samples indicate that the plastic elongation of the alloy is successfully improved from 1.0 to 3.2% by the heat-treatment. Investigation on the microstructural evolution in the heat treatment shows that an acicular alpha phase, existing in the beta lamellar structure of the as-sintered samples and harmful for its ductility, is suppressed by quenching and effectively eliminated from the heat-treated samples. Moreover, in the solution treatment, the alloy splits into a primary alpha phase and a beta phase. In the water quenching, the beta phase is transformed into a lamellar structure of secondary alpha phase and beta phase with improved ductility. As a result, the improved ductility of the heat-treated samples derives from the plastic deformation of the ductile lamellar structures and the synergic displacement of the rigid primary alpha phase.