Using of friction stir processing for obtaining of CuAl9Mn2/tungsten composite material

The paper studies samples of composite materials CuAl9Mn2/W with tungsten content of 5, 10 and 15 vol. %. The samples were produced by the method of multipass friction stir processing (FSP) with the intermixing of tungsten powder particles into the holes drilled in the matrix plates. It was found that one pass of FSP does not provide the formation of defect-free structure with homogeneous distribution of tungsten, while four passes of processing allow to achieve a homogeneous structure in the stir zone. Because of processing, the formation of intermetallic phase γ2-Al4Cu9 was observed in all the studied specimens. Increasing of the tungsten content led to an increase in the γ2-phase content due to the deterioration of the thermal conductivity of the material with tungsten. This led to the disintegration of the β-Cu3Al phase originally characteristic of CuAl9Mn2 into α-Cu(Al) solid solution and γ2-phase. Microhardness measurements showed an increase in values with increasing W content, especially at 15 vol%, indicating hardening of the material. However, the increase of tungsten content led to a decrease in the values of tensile strength, yield strength and elongation. These results indicate that copper-tungsten composites are promising as well as necessity of a balance between hardening and plasticity preservation in their design.