【摘要】 对于慢加载时拉伸速率对金属材料塑性影响的问题,目前尚无统一的认识.为此,在3.3×100～3.3×10-5s-1范围内连续调整拉伸速率,测定了几种球墨铸铁的力学性能.结果发现,对于通常认为是韧性、介韧性及脆性的球铁,其延伸率均随拉伸速率的减小而呈同一规律改变,即先是逐渐增大,至某一最大值后又逐渐减小,所得曲线呈峰状.正常状态下材料的韧性不同,峰的形状、大小及位置也不同.对于脆性材料,仅在拉伸速率3.3×10-4s-1时呈现出一定的塑性,却也表明在小应变作用下其力学性能的潜力.更多还原

【Abstract】 There is no consensus of opinion at present towards the influence of elongation on the plasticity of metallic material when applying load slowly.For this purpose, the elongation of several cast irons with nodular graphite is determined while adjusting the stretching rate continually at the range of 3.3×100s-1～3.3×10-4s-1. It is found that with the decrease of stretching rate the change of elongation of nodular iron, which is commonly considered to be of toughness, mesic toughness and brittleness, is in the same principle, i.e, the elongation increases gradually at first, decreases gradually after the reach of maximum value. So the peak shape of curves appears, toughness of materials is different, the shape, the size and place of peak of the curve are different at normal state. There appears a little plasticity only at the rate of 3.3×10-4s-1 for material, which demonstrates the latent capacity of mechanical property under applying little stain and stress.更多还原