中文摘要：

通过改变试样在热处理过程中的升温速率，研究了升温速率对激光立体成形（LSF）GH4169合金再结晶过程的影响，分析了升温速率对再结晶形核位置、再结晶晶粒长大速率和再结晶晶粒分布的影响。结果表明要使得试样发生再结晶则升温速率必须高于某一临界值，升温速率过低造成的材料内部残余应力消失会阻碍再结晶的发生；随升温速率的增加，再结晶形核位置从道间搭接区域逐渐转变为道间搭接区域和道内同时形核，有利于道间搭接区和道内再结晶晶粒尺寸差异的消除；在实验参数范围内，晶粒细化的速率随着升温速率的提高而增大。

英文摘要：

The effect of heating rate on recrystallization process of laser solid forming （LSF） GH4169 superalloy is investigated by changing the heating rate of the sample during heat treatment. The effect of heating rate on recrystallization nucleation site, recrystallization grain growth rate and recrystallization grain distribution are analyzed experimentally. The results show that the lower residual stress of the inner part of each laser scanning path as the low heating rate can hinder the recrystallization process, so in order to make the sample recrystallization the heating rate must be higher than a critical value. With the increasing of heating rate, the recrystallization nucleation site changes from the only overlapping regions of two adjacent laser scanning paths to both the overlapping regions and the inner regions of laser scanning path, and this is beneficial to the uniform distribution of recrystallization grains. Furthermore, recrystallization grain growth rate increases with heating rate increasing within the parameters used in this experiment.