连续变断面体挤压过程金属的变形特征

采用铅试料，用网格法实验观测连续变断面循环挤压法挤压时金属的流动特征。研究表明，正挤压时，金属在模腔中延伸变形成圆台体，受模具形状影响，变形程度从顶端向底端逐渐减小；圆台体镦粗时金属在高度方向从顶端至底端各层沿径向流动逐渐减小，依次连续变形成圆柱体。这种变形特点使试料在变形过程中逐渐渗透达到累积的效果，并且未出现圆柱体镦粗时的鼓形现象，也未出现因失稳导致的界面叠层。

Deformation Behaviors of Metal by Continuous Variable Cross-section Recycled Extrusion

The metal flow behviors of Pb sample was studied in continuous variable cross-section recycled extrusion using grid measuring system. The result shows that the shape of metal changes into circular cone at forward extrusion. The deformation decreases from top to bottom due to the die shape. The deformation extent of metal decreases from top to bottom along longitude direction during upset and changes into cylinder, accumulating deformation exists during processing, the shape phenomenon is not observed and the overlap due to unstable deformation does not appear when recycled extrusion is carried out.