微细黄铜板料尺寸效应

为研究微细尺度下材料的晶粒尺寸d、厚度t对其力学性能的影响,引入尺寸效应影响因子φ=t/d,在常温下对具有不同晶粒尺寸和板厚的H62黄铜薄板试样进行单向拉伸实验。结果表明,随着φ的减小,流动应力减小,延伸率下降;板料硬化指数n值,随板料厚度的增加而增大,随晶粒尺寸的增大而增大。拉伸试样均为韧窝微孔聚合型断裂,0.5mm和1.0mm厚度试样断口处韧窝多而浅,且为抛物线形,材料韧性好,塑性强;板厚0.1mm和0.2mm的试样断口韧窝深而大,硬化指数n值大,但塑性差。

Size effects research on the micro sheet metal H62 brass

In order to investigate the effects of grain size and thicknesses to material mechanical properties in the micro-scale,experiments were achieved by tensile test on H62 brass sheet metal with different grain size and thickness,then,a parameter(the ratio of sheet thickness to material grain size) was introduced to characterize size effects.The experiment results showed that the flow stress and elongation decrease as decreases;The hardening exponent n of sheet metal increases with increase of sheet thickness and grain size.All specimens show dimple fracture.The specimen of 0.5mm and 1.0mm sheets show good toughness and plasticity,while the dimples are numerous,shallow and in parabolic form.For the specimen of 0.1mm and 0.2mm sheets,the hardening exponent n is high and plasticity is low,while the dimples are big and deep.