铁磁性激光熔覆层应力的金属磁记忆评价

Stress measurement of laser cladded ferromagnetic coating with metal magnetic memory

基于压磁理论,探讨激光熔覆层应力的磁记忆评价机理.基于激光熔覆层SEM观察对磁记忆法向分量Hp(y)信号进行分析.结果表明,随应力增大,激光熔覆层磁记忆法向分量Hp(y)曲线以过零点为中心呈逆时针转动,磁畴由无序向有序转变使得Hp(y)曲线斜率逐渐变大,当应力达到520 MPa(小于试样屈服强度)时,再随应力的增大,Hp(y)曲线斜率逐渐变小.分析认为,激光熔覆层的快速凝固各向异性组织及其中界面导致激光熔覆层呈不均匀塑性变形过程是引起上述结果的主要原因,也是应力小于试样屈服极限时,Hp(y)曲线斜率随应力增大呈减小趋势变化的原因之一.

Based on piezomagnetic theory,study on stress evaluation of laser cladded coating with metal magnetic memory was introduced. With microstructural observation on the laser cladded coting by SEM,Hp（ y） signals were analyzed. The results show that as stress increasing,Hp（ y） signal rotates around zero crossing point counter-clockwisely,the slope of Hp（ y） magnetic curve increases gradually because magnetic domain transforms orderly, when stress achieves 520 MPa, the slope of Hp（ y） magnetic curve decreases as stress increases further. The inhomogeneous plastic deformation of laser claddedcoating results from anisotropic structure and interface is the main reason for the above results,and it is also an important reason for the difference between turning point of stress of curve and yield limit stress of laser cladded coating specimen.