激光冲击与渗铝复合处理对12CrMoV组织性能的影响

Effects of laser shock processing and aluminizing on microstructure and properties of 12CrMoV alloy

利用高能短脉冲激光冲击技术对渗铝后的12CrMoV合金进行了复合处理,分析了处理后12CrMoV合金表层的界面成分分布及显微组织变化对其疲劳性能的影响。EDS分析表明:12CrMoV合金渗铝后获得了具有较高的热稳定性及抗高温氧化性能的铝化物涂层。复合处理形成的铝化物涂层硬度高,韧性较低,而且粗糙度增加,在疲劳过程中易产生裂纹并快速扩展进入基体,致使高温下12CrMoV合金疲劳寿命降低。对铝化物涂层进行激光冲击强化处理不仅能使渗层组织更加致密,增加渗层与基体的结合强度,还能在渗层残留较高的残余压应力,有效提高12CrMoV合金的疲劳强度。结果表明:材料在激光冲击处理后的抗疲劳寿命得到明显提高。

The aluminized layer of 12CrMoV alloy was treated by laser shock processing （LSP） with high power and short pulse. The effects of constituent distribution and microstructure change of aluminized layer of 12CrMoV alloy on its fatigue performance were investigated. The EDS results indicated that 12CrMoV alloy obtained higher thermal stability and aluminized coatings with high-temperature oxidation resistance through aluminizing. However, aluminized coatings have high hardness, low toughness and more roughness, so the crack occurs easily and expands into the substrate fast in fatigue process. It results in fatigue life of 12CrMoV alloy reducing in high-temperature. LSP on aluminized coating not only improves the density of the layer structure and increases the bonding strength of infiltration layer and the substrate, but also leaves higher residual compressive stress in the aluminized layer of 12CrMoV alloy and effectively improves its fatigue strength. The results indicate that the anti-fatigue life of material after LSP is enhanced greatly.