Experimental and numerical studies on W–Cu functionally graded materials produced by explosive compaction–welding sintering

Herein, high-density W–Cu functionally graded materials were successfully prepared by explosive compaction–welding sintering. The minimum detonation pressure required for the explosive compaction–welding and minimum pressure needed for the powder consolidation were calculated. A method for calculating the equation of state of the porous materials was presented, and the data of the porous W–Cu composites thus obtained were used in the numerical simulation. The pressure changes in the powder layers during the explosive compaction–welding was numerically simulated, which showed that the parameters of the explosive used in the experiment were sufficient for densifying the powders. The scanning electron microscope test results exhibited that the layers of the graded materials were tightly integrated. The interface between the W–Cu particles was enriched with Cu, whereas there was no growth of the tungsten particles in the W–50 wt.% Cu layer. Tungsten and copper enrichment occurred in some regions in the W–70 wt.% Cu layer, whereas there was a growth of tungsten particles in some areas in the W–30% wt. Cu layer, the reasons for which were analyzed. The overall porosity of the three powdered layers in the five-layer gradient material was 0.36%. The contents of tungsten and copper showed a gradient trend similar to the added W–Cu composite powders. The Vickers hardness test results also exhibited a gradient trend. The shear strength between the layers was measured. The shear fractures were analyzed.