镍基高温合金DZ125激光再铸层化学研磨的实验研究

An experimental study on chemical milling of recast layer formed on Ni-base superalloy DZ125

研究了镍基高温合金DZ125激光再铸层组织特征、电化学腐蚀行为,并分析了再铸层化学研磨的优化条件,测试了研磨后基体的热疲劳性能。研究发现,DZ125合金激光再铸层主要为枝晶结构,且强化相γ′相析出较少,激光再铸层的耐腐蚀性能明显弱于DZ125合金基体。化学研磨溶液保温在60℃以上、浓度在90%以上时,再铸层的化学研磨高效可靠,研磨后基体表面光滑,无明显腐蚀发生,且基体的热疲劳性能得到明显改善。

Microstructural characteristics and electrochemical corrosion behavior of Ni-base superalloyDZ125 recast layer were investigated. The optimum condition of milling solution was analyzed, and thenthermal fatigue of the chemical-milled samples was tested. The results showed DZ125 alloy recast layerwas mainly consisted of dendrite structure with less γ′ phase precipitate. The alloy substrate was more ableto resist corrosion than recast layer. It is only when chemical milling solution is incubated at 60℃ or more,more than 90% concentration that recast layer is removed efficiently and reliably, bringing less damage tothe substrate. After chemical milling, these will generate smooth surface, and the thermal fatigue perfor?mance of alloy substrate has also significantly improved.