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研究了一种快速凝固粉末冶金高温钛合金的微观组织及其影响因素.结果表明:热等静压(HIP)成形温度可以显著地改变钛合金粉末的显微组织,当HIP成形温度为700℃时,粉末中的α′马氏体相开始微量分解,900℃时大量分解,分解产物为等轴/板条α相和晶界β相.α+β两相区HIP成形后的显微组织主要由等轴α相、板条α相和β相组成,随着温度升高,等轴α相略有长大,板条α相的长宽比显著降低;β单相区HIP成形后的显微组织为片层组织,主要由粗大的片层α相和沿原始β晶界分布的晶间α相组成.粉末粒度越小,HIP成形后的显微组织越细小.α+β两相区HIP成形并在α+β两相区进行热处理后的显微组织主要是由等轴α相和β转变组织组成的双态组织:β单相区HIP成形并在α+β两相区进行热处理后的显微组织是由等轴α相、板条α相和β转变组织组成的三态组织;α+β两相区或者β单相区HIP成形并在β单相区进行热处理后的显微组织均为较细的网篮组织.稀土Nd含量增加,显微组织的组成没有发生变化,但基体中弥散析出的稀土相数量增加,原始β晶粒尺寸明显减小.
The microstructure of a rapid solidified powder metallurgy high temperature titanium alloy and its influencing factors were studied.The results show that the microstructure of the titanium alloy powder can be significantly changed by the hot isostatic pressing (HIP) forming temperature. When the HIP forming temperature is 700 ℃ , The α ’martensite phase in the powder began to decompose and decomposed at 900 ℃, the decomposition products were equiaxed / lath α phase and grain boundary β phase. Α + β Two-phase region Microstructure after HIP formation Mainly composed of the equiaxed α phase, the lath α phase and the β phase. As the temperature increases, the equiaxed α phase slightly grows, and the aspect ratio of the lath α phase decreases significantly. The microstructure is lamellar structure, mainly composed of coarse lamellar α phase and intergranular α phase distributed along the original β grain boundary.The smaller the particle size of powder, the finer the microstructure after HIP formation.The smaller the α + β two-phase The microstructure after zone HIP formation and heat treatment in the α + β two-phase region is mainly a bimodal structure composed of equiaxed α-phase and β-transformed structure: β single-phase region HIP is formed and is carried out in the α + β two-phase region The microstructure after the heat treatment is a three-state structure consisting of an equiaxed alpha phase, a lath alpha phase and a beta-transformed tissue; an α + β two-phase region or a β single-phase region HI P microstructure after heat treatment in β single-phase zone are fine baskets.The content of rare earth Nd increases, the composition of the microstructure does not change, but the amount of rare earth phase dispersed in the matrix increases, the original β grain size is significantly reduced.