中文摘要：

针对粉末材料低塑性的特点,在室温条件下采用包套-等径角挤压工艺（PITS-ECAP）将纯铜粉末颗粒直接固结成高致密度块体细晶材料。结果表明,包套-等径角挤压工艺对粉末材料具有有效的致密和细化效果。4道次PITS-ECAP工艺变形后,试样X、Y、Z面均受到剧烈剪切作用,晶粒尺寸得到明显细化,显微组织呈细长条带流线状,且分布较为均匀;试样整体组织达到完全致密,平均显微硬度高达1 470 MPa。在PITS-ECAP工艺变形过程中,剧烈塑性剪切变形、较高静水压力和有效应变积累是保证粉末材料致密度大幅度提高以及显微组织有效细化的主要原因。

英文摘要：

In this study,pure Cu powder particles were successfully consolidated into full dense bulk material with fine grains at room temperature by the powder-in-tubes equal channel angular pressing（PITS-ECAP）.After four passes of PITS-ECAP via route Bc,microstructures at X,Y and Z planes of each sample were all severely sheared and elongated along a certain direction with fine banded structures;the grains were greatly deformed and refined with uniform size distribution;and the processed consolidate reached full density and its microhardness was greatly improved,which achieved up to 1470 MPa.It is indicated that it is severe plastic shear deformation,high hydrostatic pressure and effective strain accumulation that ensures a high density and a fine microstructure of powder consolidate.