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应变硬化与应变速度硬化提高了塑性变形时材料的流变应力,它们反映了材料抵抗不稳定流动的能力。在拉力试验时,试样开始颈缩的真应变等于应变硬化指数n。应变速度敏感性m对于从开始颈缩至断裂之间的总应变有显著的影响。当m大于零时,随着m加大,该部分应变增加。n和m值较大的材料在通过模孔拉伸和薄板深冲时具有较大的塑性变形能力。
Strain hardening and strain hardening increase the flow stress of the material during plastic deformation, which reflects the ability of the material to resist unsteady flow. In the tensile test, the true strain at which the specimen begins to neck is equal to the strain hardening index n. The strain rate sensitivity m has a significant effect on the total strain from the beginning of the neck down to the break. When m is greater than zero, as m increases, the strain increases. Materials with larger values of n and m have greater plastic deformation capacity when stretched through die holes and deep drawn sheets.