采用预合金粉末热等静压技术制备TiAl-4522XD合金试样，研究热等静压工艺参数(热等静压温度、粉末 粒度等)对TiAl-4522XD 合金组织和性能的影响。 发现热压温度为1200℃时无法实现致密化，组织中残留有原始颗粒 边界，使得基体强度较低；热压温度为1260℃时组织能完全致密化，原始颗粒边界消失，合金抗拉强度显著提高；热压 温度升高到1300℃时，γ晶粒和硼化物快速长大，γ/α2相边界处在热应力下出现微裂纹， 合金室温和高温抗拉强度相 对1260℃时降低。对不同粒度的合金粉末分别进行了1260℃+4h的热等静压，发现其密度均能达到TiAl-4522XD合 金理论密度，但是粒径范围为150~212和45~212μm时，粉末颗粒变形量不均匀，热压试样中局部位置存在微裂纹，而 粒度范围为45~150μm时，热压试样组织均匀细小且无明显缺陷。此外，TiAl-4522XD合金热等静压装粉除气真空度必 须达到10-3Pa，否则会影响组织致密度和粉末变形均匀程度，导致原始颗粒边界处产生裂纹。结果表明，最佳工艺为：采 用粒径范围45~150μm的粉末在1260℃/4h/10-3Pa 的参数下进行热等静压，热压后能够获得均匀、致密的近γ组织， 其室温抗拉强度为(698.0±2.0)MPa，高温抗拉强度为(504.5±2.5)MPa。

 A prealloyed powder hot isostatic pressing (HIP) technique was utilized to fabricate a TiAl-4522XD alloy. The effects of HIP processing parameters (temperature and powder particle size) on the microstructure and mechanical properties of TiAl-4522XD alloys were investigated. Densification cannot be achieved at a HIP temperature of 1 200 ℃, with prior particle boundaries (PPBS) in the microstructure, resulting in a low matrix strength. At a HIP temperature of 1 260 ℃, complete densification is achieved, the PPBS disappears, and the tensile strength of the alloy significantly increases. When the hot pressing temperature is increased to 1 300 ℃, γ grains and borides rapidly grow, microcracks appear at the γ/α2 phase boundaries under thermal stress, and the tensile strengths at both room temperature and high temperatures decrease compared with those at 1 260 ℃. HIP samples with different particle sizes were fabricated at 1 260 ℃ for 4 h. The results show that all the samples reached the theoretical density of the TiAl-4522XD alloy. For the particle size ranges of 150~212 and 45~212 μm, the deformation amount of powder particles is uneven, with microcracks present in the hot-pressed samples; for the particle size range of 45~150 μm, the hot-pressed samples have uniform and fine microstructures without obvious defects. Additionally, the vacuum degree during powder loading and degassing must reach 10-3 Pa; otherwise, it affects the density of the microstructure and the uniformity of powder deformation, leading to  cracks at the PPBS. On the basis of these results, the optimal HIP process is achieved: the powder particle size range is 45~150 μm, and the HIP parameters are 1 260 ℃/4 h/10-3 Pa. Under these conditions, a uniform and dense near-γ microstructure is obtained, with a room temperature tensile strength of (698.0±2.0) MPa and a high-temperature tensile strength of (504.5±2.5) MPa.