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采用激光沉积制造(LDM)技术制备了γ-TiAl合金(Ti-48Al-2Cr-2Nb)试样,并对不同工艺条件(激光功率和扫描速度)下试样的相组成、显微组织及显微硬度进行了分析。结果表明,经LDM工艺制备的γ-TiAl合金显微组织特征为等轴状的初生晶粒内包含有细小层片状的γ、α2相和B2相;扫描速度恒定,随着激光功率的增加,初生等轴晶晶粒尺寸逐渐增大,晶内的α2相和B2相含量逐渐增加,γ相含量降低,合金显微硬度逐渐增大;激光功率恒定,随着扫描速度的增加,初生等轴晶晶粒尺寸逐渐减小,晶内的α2相和B2相含量逐渐减少,γ相含量增加,合金显微硬度逐渐增大。经综合分析认为激光功率1 200 W、扫描速度7mm/s为最佳的γ-TiAl合金LDM工艺参数。
The samples of γ-TiAl alloy (Ti-48Al-2Cr-2Nb) were prepared by Laser Deposition Manufacturing (LDM). The phase composition, microstructure and microstructure of the samples were characterized under different process conditions (laser power and scanning speed) Microhardness was analyzed. The results show that the microstructure of γ-TiAl alloy prepared by the LDM process is characterized by the equiaxed primary grains containing fine lamellar γ, α2 phase and B2 phase; the scanning speed is constant, with the increase of laser power , The size of primary equiaxed grains gradually increases, the content of α2 phase and B2 phase in the grains gradually increases, the content of γ phase decreases, and the microhardness of the alloy gradually increases; the laser power is constant, and as the scanning speed increases, Axial grain size decreases gradually, the content of α2 phase and B2 phase decreases gradually, the content of γ phase increases, and the microhardness of the alloy gradually increases. The comprehensive analysis shows that the laser power of 1 200 W, the scanning speed of 7mm / s is the best γ-TiAl alloy LDM process parameters.