MACROSCOPIC RESPONSE AND MICROSCOPIC MECHANISM OF ZIRCALOY-4 UNDER NONPROPORTIONAL LOADING
非比例加载Zr—4合金的宏观响应及其微观机理

Monotonic and cyclic plastic deformation behaviour and microscopic mechanism of zircaloy-4 under biaxial tension loading along different loading paths were investigated. The results show that an obvious stress delay appears in comparison with the strain increment vector after the turning point of a strain path. The equivalent stress suddenly drops then increases, and the firstly softening and subsequently haxdening degrees are related to the turning angle values,the path length and turning direction. Therefore, the influence of the deformation history and the coupled effects among strain components on the response can not be neglected. By TEM, the deformed dislocation configurations are parallel dislocation lines in uniaxial tension with constraint condition, a lot of free dislocation lines between channeals in double-triangle, and embryonic cells in elliptical and circular loading, respectively. The correlation between macroscopic deformation behaviour and microscopic deformation structure is discussed, finally.