纯钛微镦粗过程的试验研究

摘要

在微成形试验机上利用自制的模具对纯钛圆柱试样进行微镦粗试验，研究试样尺寸、应变速率对微塑性成形流变应力的影响。研究表明：相同温度和压下速度下，随着试样尺寸的降低，流变应力呈明显的减小趋势，这种现象可以用表面层模型进行解释；流动应力随着应变速率的提高有增大的趋势，这是由于应变速率的提高导致位错与晶格缺陷等的相互作用来不及发生，致使材料的流变应力增大。%In this paper ,the micro upsetting experiments of pure titanium cylindrical specimens were carried out on the micro plastic forming machine ,using the self‐made micro forming die .The effects of specimen size ,strain rate on the flow stress and formability of pure titanium were investigated .Research shows that :the flow stress of specimens decreases with the decrease of specimen size , this phenomenon can be explained by the surface layer model ;the flow stress increases with the increase of the rate ,which is due to the interaction between dislocation and lattice defects .