In order to study the grain evolution and precipitation phase of IN718 alloy treated by laser peening(LP)holding at elevated temperature, the LP experiment of different power density and high-temperature holding test were carried out. The microhardness of the samples at different temperatures and laser power density was analyzed. In addition, the grain morphology of the samples was observed by Scanning Electron Microscope(SEM), and the high-temperature precipitated phase of IN718 alloy was analyzed by Energy Dispersive Spectrometer(EDS). The results show that the microhardness of the LPed samples is higher than that of untreated samples, and the microhardness of the LPed samples is reached the maximum at 700 ℃, which is 348. The grain size of the LPed samples is reduced from the original 45 μm to 20-30 μm, and increased to 35 μm after the high-temperature hol-ding test. As the temperature rose, the δ precipitated phase in the IN718 material increased gradually, and the precipitated phase of TiN was observed. Finally, according to the grain evolution law and precipitated phase analysis at elevated temperature, the high-temperature strengthening mechanism of the LPed IN718 alloy was proposed.
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