Abstract: The extrusion strengthening of the copper being in the tail of CuW80/Cu integrated contact material,which was prepared by powder metallurgy sintering,was investigated.Microhardness of the copper after extrusion was measured along longitudinal and horizontal sections,and correspondingly,microstructure was observed by three-dimension video microscopy and transmission electron microscopy (TEM).The hardness of the copper increased remarkably after extrusion,which was 200% higher than that before extrusion,indicating that extrusion was one of the efficient ways to strengthen the copper in the tail of CuW80/Cu integrated contact material.In horizontal sections,the hardness of copper after the extrusion increased from inner to surface,while in longitudinal sections,the hardness of copper after the extrusion increased far away from interface of CuW80/Cu.The results of TEM observation showed that there were still some dislocation tangles even though the extrusion was small,and cell dislocation structures formed after serious extrusion.