连续/脉冲CO_2激光熔覆高温合金K403

Research on Continuous/Pulse Laser Cladding Superalloy K403

针对飞机叶片激光熔覆的特殊要求,利用横流CO2激光器及加工系统,系统地研究了连续/脉冲CO2激光对K403材料熔覆质量的影响规律。结果表明,相同线能量下脉冲激光熔覆与连续激光熔覆相比,外表光滑、平整、熔覆层与基体的界面结合完整,稀释率低20%,熔覆层硬度高5%,热影响区小50%。脉冲激光熔覆K403材料减少了合金元素的聚集和低熔点共晶组织的形成,缩小了"液态薄膜"的产生范围,同时由于基材变形小,降低了冷却凝固过程中的拉应力,较高的过热度使熔覆层液体与基体液体充分混合,降低了基体的脆性,解决了K403材料连续CO2激光熔覆易产生裂纹的问题。

Aiming at the special requirement of laser cladding on aereoengine blade,the influences of continuous/pulse beam on cladding performance for K403 substrate was studied experimentally on a transverse CO2 laser and its processing system,compared with continuous laser beam,by using pulse laser beam,the hardness of cladding layer increased for about 5%,while the duty rate and area of heat-affected zone decreased for about 20% and about 50%,respectively.Cladding with pulse laser beam could weaken the gathering of alloy elements and the formation of low melting eutectic structure,resulting in the absence of liquid state membrane on grain boundary.In addition,the tension stress in solidification is greatly reduced during pulse laser cladding due to the less deform of substrate,and a higher degree of superheat induced fully mixing of the melting pool and decreased the brittleness of substrate,so,the heat cracking behavior of K403 substrate under continuous laser beam cladding was avoided under pulse laser beam cladding.