微波辐照对iPP在Al/iPP/Al界面层残余应力的影响

A STUDY ON CRYSTALLINE RESIDUAL STRESS OF iPP SURFACE LAYER IN Al/iPP/Al UNDER THE INFLUENCE OF MICROWAVE IRRADIATION

采用薄膜X射线衍射(TF-XRD)方法研究了微波辐照后Al/iPP/Al夹心材料中iPP界面宏观残余应力,微观应力和点阵静畸变应力的变化,结果表明,微波辐照后iPP的宏观残余张应力减小。垂直于[300]晶面(β晶形)的晶粒尺寸增大,β晶形生长趋于完善,晶格微观畸变减小,微观应力减小,α晶形微观应力增大。β晶形的点阵静畸变应力和应力能量小于α晶形,这是引起α→β晶形转变的主要原因。

The residual stress of iPP surface layer in Al/iPP/Al under influence of microwave irradiation was investigated by TF-XRD. Depending on the irradiation time, the macro residual stress, micro stress and lattice static distortion stress were calculated. The results show that the macroscopic residual stretch stress of irradiated iPP samples is dropped from about 12 MPa to 4 MPa. D_([300])(stand for β-form phase) becomes larger from about 4nm to 10nm as the irradiation time increased, and β-form iPP becomes more perfect. However, for the α-form phase, D_([110]) almost remains stable. Moreover, the microscopic distortion coefficient ε__([300]) which decreases from approximately (0.03) to (0.018) becomes smaller than ε__([110]) parallel to the irradiation time, so the microscopic stress of β-crystal is decreased. In addition, The lattice static distortion energy of α-form heavily raises from 2 MPa to 6 MPa, but the lattice static distortion energy of β-crystals remains constant at about (1.5) MPa and is very smaller than of α-crystals with the same irradiation time. The lattice distortion energy is the major part of the plastic deformation, therefore, it suggests that the lattice static distortion energy is the main cause of α→β crystalline transformation.