等离子喷焊熔覆层的磁记忆应力评价*

运用金属磁记忆检测技术对等离子喷焊熔覆层进行应力评价。对标准等离子喷焊熔覆层试样进行静载拉伸试验，检测不同拉伸应力下熔覆层表面的磁记忆信号法向分量H_p(y)和切向分量H_p(x)，分析H_p(y)梯度值K及H_p(x)均值H_p(x)_avg随拉伸应力的变化。结果表明：在弹性阶段，H_p(y)曲线随着拉伸应力的增大逆时针旋转，K值随着拉伸应力的增大呈指数增加;同时H_p(x)_avg随着拉伸应力的增大而线性增加。在塑性阶段，H_p(y)曲线随着拉伸应力的继续增大而顺时针旋转且K值减小;同时H_p(x)_avg随着拉伸应力的增大而线性减小。基于等离子喷焊熔覆层微观组织和磁机械效应探讨了熔覆层应力的磁记忆评价机理。

Stress Evaluation of Plasma Sprayed Cladding Layer Based on Metal Magnetic Memory Testing Technology

For achieving the stress evaluation of plasma sprayed cladding layer based on metal magnetic memory testing technology, static tensile tests of plasma spraying specimen are carried out. Meanwhile, the magnetic signal is measured through the tensile tests. The normal component of magnetic signal,Hp(y), and its gradientK, the tangential component of magnetic signal,Hp(x), and its average value,Hp(x)avg, changing with tensile stress are investigated. The results indicate that theHp(y) rotated anticlockwise and its gradientK increase exponentially, andHp(x)avg increases linearly with the increase of stress in the elastic stage. While in the plastic stage, theK andHp(x)avg decrease with the further increase of stress. The mechanism of stress evaluation of plasma sprayed cladding layer is discussed from viewpoint of the microstructure and magneto-mechanical effect.