Study on Strengthening of the Solid Contact Alloy CuW80/Cu

Abstract

The strengthening effects of the Cu-80 wt.% W (CuW80) alloy and the copper parts in Cu-80wt.% W /Cu (CuW80/Cu) solid contact alloy, which was sintered and infiltrated prepared by powder metallurgy, were investigated. The effects of different compressive deformation on microstructure and properties of the CuW80 were studied. Furthermore, the influences of HextrusionH on copper parts, the carrier material of the solid contact alloy CuW80/Cu were also investigated. The results show that the tungsten and copper phases are closely bonded by physical bond in the form of pseudo-alloy and the copper phase is homogeneously dispersed within the tungsten framework. The hardness of the CuW80 increases with increasing compressive deformation. Especially, the hardness of the copper parts in CuW80/Cu increases remarkably after extrusion and the maximum value can reach 200%. The hardness increases from the inner to the surface and is proportional to the distance departing from the interface of the CuW80 and Cu. TEM observation shows that the dislocation tangles exist, even inside the dislocation cell, in copper grains after extrusion.

Extrusion Strengthening and Its Numerical Simulation of the CuW80/Cu Solid Contact Material

“…The remainder Cu segments of the cylinder CuW80 /Cu samples were machined into shoulder shape samples with different dimensions, as shown in Fig.1. In extrusion process, the tail Cu segment would suffer violent plastic deformation from 54%--136% with dimension change of samples (2) . The micro-hardness tests were carried out CuW80/Cu sample with a load of 0.4905N for 15s using a HX-1000 Vickers hardness tester.…”

“…The CuW80 alloy, with high electrical and thermal conductivity, good arc and electric erosion resistance, and high resistance to thermal and mechanical impacts, possesses fairly comprehensive properties (1) (2) . Therefore, it meets fully the characteristics of contact materials that high-voltage switching devices require, and is widely used (3)- (5) .…”

“…They are traditionally manufactured by electron beam welding, soldering, percussion welding or brazing to connect CuW with Cu. Unfortunately, the properties of the joining place in the contact materials can not fully meet the technical requirements since the existent welding technique sometimes brought in some microstructural defects around the interface area (2) (6) . An important process for manufacturing solid contacts is by melting to make the contact of Cu-W bond with the tail of alloy (6) .…”