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采用激光成形修复技术制备了TC4合金锻件的面修复试样,对修复试样的显微组织、拉伸性能、低周疲劳性能进行了研究。激光修复区组织由粗大原始β柱状晶粒及晶内细长的α针及编织细密的α+β板条组织组成,热影响区组织呈现从锻件基体组织向修复区组织的连续变化,修复区与锻件基体为致密的冶金结合。对两组面修复试样分别进行去应力退火和去应力退火+喷丸处理后,测试获得了激光成形修复TC4合金锻件的低周疲劳曲线,由于面修复试样的拉伸性能与锻件相比强度高而塑性低,因此两组修复试样的疲劳寿命在低应变区高于TC4模锻件,此区强度对疲劳寿命起主要作用;而在高应变区低于模锻件,此区塑性对疲劳寿命起主要作用。修复试样经喷丸处理后,无论在高应变区还是在低应变区,其疲劳寿命都有所提高,并且在高应变区接近TC4模锻件水平,而在低应变区则高出模锻件一个数量级。
The surface repair samples of TC4 alloy forgings were prepared by laser forming and repairing technique. The microstructure, tensile properties and low cycle fatigue properties of the repaired samples were studied. The laser repair zone consisted of coarse primary β-columnar grains and elongated α-stitch and fine braided α + β lath in the HAZ. The HAZ showed continuous changes from the matrix of forgings to the repair area. The repair area Metallurgical combination with forging matrix for compact. The low cycle fatigue curves of TC4 alloy forgings were obtained by laser annealing and stress relief annealing and shot peening respectively. The tensile properties of the surface repair samples were compared with forgings High strength and low plasticity, the fatigue life of the two repaired specimens is higher than that of TC4 die forging in the low strain region, and the strength of this region plays a major role in the fatigue life; while in the high strain region, the fatigue life is lower than that of forgings, Life plays a major role. The fatigue life of the repaired sample after shot peening has been improved both in the high strain zone and in the low strain zone, and is close to the TC4 forging level in the high strain zone and higher in the low strain zone Magnitude.