铝合金板材拉伸后的表面橘皮与其力学性能及表面粗糙度的关系

Relation between Surface Orange Peel,Mechanical Properties and Surface Roughness of Tensile Aluminum Alloy Sheet

对铝合金板材进行拉伸试验,对比分析了有无表面橘皮对拉伸性能、拉伸断口形貌、表面粗糙度和纳米硬度的影响。结果表明:有橘皮试样的总伸长率、均匀伸长率和r值均低于无橘皮试样的,但前者的应变硬化指数要高于后者的;有橘皮试样的表面粗糙度各指标均高于无橘皮试样的,而且前者的滑移带和韧窝区均较后者的宽,并在滑移带交汇处有微裂纹,但其剪切唇较后者的窄;有橘皮试样的弹性模量和纳米硬度均高于无橘皮试样的,但其压痕的最大压入深度和塑性变形深度较后者的小。

Effects of with/without surface orange peel on tensile properties, surface roughness and nano-ardness of aluminum alloy sheet were analysed by tensile testing. The results show that the total elongation, uniform elongation, r value of the samples with orange peel were lower than that of the samples without orange peel, but the strain hardening exponent of the former was higher than that of the latter. The surface roughness parameters, width of sliding band and dimple area of the samples with orange peel were higher or larger than those of the samples without orange peel, and micro-cracks could be found in the intersection of sliding band in the samples with orange peel, but the shear lip of the cracks was more narrow. The elastic modulus and nano-hardness of the samples with orange peel were high than those the samples without orange peel, but the maximum depth of indentation and plastic deformation depth of the former were smaller than those of the latter.