Effect of laser-quenching substrate on interfacial shear strength of chromium plated coatings
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摘要: 为了揭示激光淬火预处理基体提高镀铬身管寿命的机理,采用多裂纹拉伸技术分别对激光淬火处理和激光未处理基体上的镀铬层界面剪切强度进行了测量,发现激光淬火基体可以提高镀铬层界面剪切强度77.7%,并从基体与铬层的界面材料结构和力学两个方面进行了分析。结果表明,激光预处理的界面是连续过渡的,而原始基体的界面存在一个过渡;激光淬火基体表面残余压应力的存在提高了铬层的断裂应力;基体表面硬度的提高减小了最大裂纹间距。Abstract: Based on the real condition that laser quenching steel substrate could improve the service life of chromium-plated gun bore,the interfacial shear strengths of Cr-plating coating on laser re-quenching substrate and laser non-treating one were measured by multi-cracks tensile method respectively.The experimental results show that the interfacial shear strength is increased by 77.7% through laser re-quenching steel substrate.The analysis of interface structure between substrate and Cr-coating shows that the interface of laser pretreatment is a continuous transition,while there is an over-layer on the original interface.The mechanical model analysis shows that the compressive residual stress in the laser processing zone could increases fracture stress of chromium coating and the improvement of substrate surface hardness decreases maximum crack spacing.The synthetic result of above two effecting factors is that the interfacial shear strength is increased by laser re-quenching substrate.
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