冷轧Cu板动态压缩力学性能各向异性的研究

利用Instron电子拉伸机和Split-Hopkinson压杆(SHPB)实验装置,研究了准静态和动态压缩条件下冷轧和退火Cu板法向、轧向、横向的力学性能.不同应变率下的应力-应变曲线表明:冷轧和退火Cu板的流变应力均随应变率的增加而增加,表现出明显的应变率强化效应.冷轧Cu板准静态和动态压缩力学性能均呈现明显的各向异性:横向屈服强度最大,轧向最小,且低应变程度下的流变应力也具有同样规律.退火Cu板呈现近似各向同性.考虑准静态和动态变形时可能的塑性变形机制,基于微观晶体塑性变形理论的Taylor模型可定性地解释冷轧Cu板压缩力学性能的各向异性.

INVESTIGATION ON ANISOTROPY OF DYNAMIC COMPRESSIVE MECHANICAL PROPERTIES OF COLD-ROLLED Cu SHEET

The quasi–static and dynamic compressive mechanical properties of cold–rolled and annealed Cu sheets were investigated by means of Instron apparatus and Split–Hopkinson pressure bar (SHPB) technology, respectively. Cylindrical specimens of textured Cu sheets, which were cut with the
cylinder axes along the rolling direction (RD), transverse direction (TD) and normal direction (ND), were compressed at strain rates in the range of 10⁻³ to 10³ s⁻¹. The compressive stress-strain curves show all that the flow stresses for both cold rolled and annealed Cu sheets increase with the increase of strain rate and the obvious effect of strain rate hardening has been observed. The quasi–static and dynamic compressive mechanical properties of the cold rolled Cu sheet exhibit pronounced anisotropy, both the yield strength and flow stresses at the low deformation degree for the TD direction are the maximum, while those for the RD direction are the minimum. The properties of annealed Cu sheet are isotropic. Taking into account of possible mechanism for quasi–static and dynamic plastic deformation, the mechanical anisotropy of textured Cu sheets could be explained qualitatively by Taylor model based on the microscopic crystal plasticity theory.