Fabrication of W/Cu Functionally Gradient Materials by Multi-Billet Extrusion

Abstract

W/Cu functionally gradient materials (FGMs) are fabricated by a novel process—multi-billet extrusion (MBE). Different W/Cu superfine powders made by mechanical alloying (MA) are used to improve the sinterability of W/Cu compacts. Good quality of three-layer W/Cu extrudes are obtained after confirming the extrusion parameters and the type and the content of binder during extrusion process. The green products are pressureless sintered at the temperature range of 1100-1300 oC for 1 h. W/Cu FGMs with relatively high density and high homogeneous microstructure are attained after sintering at 1200 oC for 1 h. The mechanisms for the enhance of sinterability and improvement of density of the mechanical alloyed (MAed) W-Cu powder products have been discussed. X-ray diffraction and scanning electron microscope are used to identify and observe phase constitution and microstructure, respectively.