激光预加工对铝化物渗层低温成形工艺的影响

Effect of Laser Pretreatment on the Formation Process of Aluminide Coating at Low Temperature

目的研究K4169镍基高温合金表面激光熔凝预处理对铝化物渗层制备温度的影响。方法先对镍基合金进行表面激光熔凝处理,分析表面熔凝层显微组织变化,再采用包埋渗法制备铝化物渗层,对比研究熔凝处理前后对渗层形成温度的影响。结果经激光熔凝处理后,合金试样表层晶粒显著细化;预处理后的合金试样表面经900℃保温5 h所制备的渗层,与未处理的经1050℃保温5 h所制备的渗层具有相似的厚度及组织结构特征。结论激光熔凝预处理可有效降低镍基合金表面铝化物渗层的成形温度,减轻渗层成形时高温长时处理对基体合金力学性能的影响。

The work aims to study the effect of laser remelting pretreatment on the preparation temperature of aluminide coatings on K4169 nickel base superalloy.The alloy surface was treated by laser remelting firstly,and the microstructure change of surface remelting layer was analyzed.Then the influence of laser remelting on preparation temperature of modified aluminide coatings was investigated.The results showed that the surface grain of the alloy was remarkably refined after the laser remelting.Both the thickness and the microstructure of the coating on the pre-treated alloy prepared at 900℃for 5 h were similar with those of the coating on the untreated alloy prepared at 1050℃for 5 h.It can be seen that laser remelting pretreatment can effectively reduce the forming temperature of nickel base alloy,and thus reduce the influence of the long-time coating preparation process on the mechanical properties of the alloy.