Inspection of W Cu gradient composites fabricated via combustion synthesis infiltration with CuO Al thermit under the ultra-gravity field

The adiabatic temperature of CuO-Al thermit adding W particles was calculated and analyzed. Thermit compact of CuO-Al with 20% mass fraction of W particles addition was ignited in the ultra-gravity field, through which the W-Cu composites was obtained. The results of microstructure inspection indicate that the low mass fraction of W displays inhomogeneous distribution. Along with the centrifugal direction, the compact of pure W particles is put under the compact of CuO-Al-W which can be ignited in the ultra-gravity field then the liquid Cu production with high temperature will infiltrate into the W compact. The inspection results of bulk W-Cu composites alloy indicate that the W mass fraction continuously gradient changes like: 60%-65% in the bottom, 80%-89% in the medium and low at the top(<40%), for inhomogeneous distribution with chains and clumps characteristic structure on the top. The hardness measurement and XRD inspection further verify the conclusion. The formation mechanism is also primarily analyzed and discussed, which indicates that W mass fraction continuously gradient variation is resulted in the characteristic aspects of the ultra-gravity SHS infiltration technique.