微观组织及残余应力对瑞利波评价激光熔覆层应力的影响  

Influence of Microstructure and Residual Stress on Surface Stress Measurement of Laser Cladding Layer by Rayleigh Wave

作　　者：董世运[1] 闫晓玲[1,2] 徐滨士[1] 

机构地区：[1]装甲兵工程学院装备再制造技术国防科技重点实验室,北京100072 [2]北京理工大学机械与车辆学院,北京100081

出　　处：《机械工程学报》2015年第24期50-56,共7页Journal of Mechanical Engineering

基　　金：国家重点基础研究发展计划(973计划;2011CB013403);国家自然科学基金(50975287)资助项目

摘　　要：采用瑞利波评价激光熔覆层表面应力,结合静载拉伸试验,建立Fe314激光熔覆层中瑞利波的声弹关系曲线;通过对声弹关系曲线拟合实现对激光熔覆材料声弹系数的标定,在此基础上建立声弹公式;通过试验验证声弹公式评价激光熔覆层表面应力的可行性。分析激光熔覆层微观组织及残余应力对应力评价结果的影响,试验结果表明,这两种因素会显著影响熔覆层表面应力评价结果,采用声弹公式计算出的初始应力校准之后,理论计算结果与实际加载值更为接近,并且误差保持在可接受的范围之内。此外,由于静载拉伸过程中各向异性激光熔覆层变形不均匀,瑞利波检测应力试验中高应力阶段的误差明显大于低应力阶段误差。Rayleigh wave is employed to evaluate surface stress of laser cladding coating, combined with static load tensile test, acoustoelastic relation curve of Rayleigh wave propagating in Fe314 laser cladding layer is established; By fitting the acoustoelastic relation curve, laser cladding material acoustoelastic coefficient are calibrated and the acoustoelastic formula is established based on this. The experimental results indicate that the acoustoelastic formula can be used to evaluate surface stress of laser cladded coatings. Then it analyzes effects of microstructure and residual stress of the laser cladded coating on surface stress experimental values, which shows the effects are significant. The experimental results are close to the actual load after being calibrated by the initial stress from acoustoelastic formula calculation. Due to the inhomogeneous deformation of anisotropic laser cladding layer during tensile process, the error of high stress stage is significantly greater than that of low stress phase when Rayleigh wave is employed to detect surface stress of Fe314 laser cladding layer.

关 键 词：微观组织 应力 瑞利波 激光熔覆层 

分 类 号：TB115[理学—数学]