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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 12CrMoV alloy after aluminizing was treated by high energy and short pulse laser shock technique. The interface composition distribution and the microstructure changes of 12CrMoV alloy after treatment were analyzed. EDS analysis showed that the aluminide coating with high thermal stability and high temperature oxidation resistance was obtained after aluminizing the 12CrMoV alloy. The aluminide coating formed by the composite treatment has high hardness, low toughness and increased roughness, which is easy to crack and rapidly expand into the matrix during the fatigue process, resulting in the decrease of the fatigue life of the 12CrMoV alloy under high temperature. The laser shock treatment on the aluminide coating not only makes the microstructure of the coating more dense, increases the bonding strength between the coating and the matrix, but also maintains a higher residual compressive stress in the coating and effectively improves the fatigue strength of the 12CrMoV alloy. The results show that the fatigue life of the material after laser shock treatment is obviously improved.