将基材预热至100 ℃和400 ℃,采用激光沉积制造技术制备了直接过渡TA15/GH4169复合结构,研究了预热温度对TA15/GH4169微观组织、残余应力及显微硬度的影响。结果表明:基材预热对复合结构成形质量的影响较大;基材未预热时,复合结构在界面处断裂;预热基材至400 ℃后,成形质量得到了改善,在界面处形成了厚度约为0.33 mm的过渡区;随预热温度升高,GH4169侧的残余应力明显降低;预热基材至100 ℃时,残余应力值较未预热时降低了21.59%,预热至400 ℃时,残余应力降低了33.19%;复合结构的显微硬度随预热温度升高呈轻微下降的趋势,在同一预热温度下,过渡区的显微硬度最高;预热基材至400 ℃时,过渡区硬度较TA15侧提高了91.2%。

In this study, a direct transition TA15/GH4169 dual alloy composite structure is prepared using the laser deposition manufacturing technique at preheating substrate temperatures of 100 ℃ and 400 ℃. Further, the effect of the preheating temperature on the microstructure, residual stress, and microhardness of the TA15/GH4169 interface is investigated. Based on the results, substrate preheating can be concluded to considerably influence the forming quality of the composite structure, whereas the non-preheated substrates produce defects at the composite structure interface. The forming quality improves when the preheating temperature is 400 ℃, and a gradient transition zone of approximate 0.33 mm is formed at the composite structure interface. The residual stress on the GH4169 side significantly decreases when the preheating temperature is increased from 100 ℃ to 400 ℃. The residual stress value reduces by 21.59% when the substrate is preheated to 100 ℃, whereas it reduces by 33.19% when the substrate is preheated to 400 ℃. The microhardness of the composite structure slightly decreases with an increase in the preheating temperature. At the same preheating temperature, the microhardness of the transition zone is the highest. At 400 ℃, the microhardness of the transition zone increases by 91.2% compared with that of the TA15 side.