激光冲击强化提高K403铸造高温合金疲劳性能

采用YLSS-M60U型高能Nd:YAG激光器,对发动机高压涡轮叶片材料K403/K3铸造高温合金试片进行激光冲击强化处理,强化工艺参数为:激光能量3J,光斑直径2.6mm,脉宽20ns,波长1064nm,吸收保护层为铝箔,约束层为水,搭接率50%,冲击3次。强化后,在420MPa应力水平下进行了室温高周振动疲劳测试,并进行了扫描电镜观察和X射线衍射仪物相分析。研究结果表明:激光冲击强化后,试片疲劳寿命是原始状态试片寿命的2.4倍,激光冲击强化的强冲击波作用使金属发生高应变率塑性变形,以及随之产生的较大较深残余压应力,是金属疲劳性能提高的主要原因。

Laser shock processing for improving fatigue property of K403 cast superalloy

The high-energy Nd: YAG laser YLSS-M60U was adopted for laser shock processing on K403/K3 cast superalloy test specimen from pressure-turbine blade materials of a certain type of engine. The processing parameters are: laser energy 3 J, spot diameter 2.6 mm, laser pulse 20 ns, laser wave length 1064 nm. An aluminium foil was used as the protection coating, along with water as the restraint layer, the overlap rate reached 50% after 3 times of shocking. The high-cycle fatigue (HCF) test was conducted under the room temperature at stress level of 420 MPa as well as the SEM observation and XRD (x-Ray diffraction) analysis after laser shock processing. The study shows that the leading reasons for improving the fatigue property of metal involve that the fatigue life of the test specimen was 2.4 times longer than the original after laser shock processing, the strong shock waves plastically deform the metal with high-strain rate and generate much larger and deeper residual compressive stress.