The microstructure of laser metal forming DZ125L superalloy was studied first. The non-equilibrium microstructure is dense, the primary spacing of dendrites is about 5μm; the generated supersaturated solid solution inhibits y' phase precipitation and punctuated MC carbides precipitates at the grain boundaries. Unless the necessary heat treatment, it couldn't be used directly. Studies of microstructure and micro-hardness on five kinds condition of heat treatment were carried out. The results show that the homogenization and solution treatment is necessary, but the time must be strictly control; the aging time can be reduced properly. The micro-hardness of the sample which fabricated with heat treatment is the lower than that with as deposit,as the microstructure is dense and strengthening phase MC carbide precipitates at grain boundary.%研究激光金属成形DZ125L高温合金的组织,其形成的非平衡组织致密,一次枝晶间距约5μm；生成的过饱和固溶体抑制γ'相析出,且晶界析出点状不连续MC碳化物.这无法满足高温合金直接使用要求,需进行必要热处理.因此研究了5种热处理状态下的组织和显微硬度,结果表明均匀化和固溶处理十分必要,但需严格控制时间；时效处理时间可以适当减少.经过热处理试样的硬度比未经过过热处理试样硬度低,主要原因是激光金属成形组织细密,晶界析出大量强化相MC碳化物.
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