Properties of Cu-W Functionally Graded Materials Produced by Segregation and Infiltration

Abstract

The Cu/W functionally graded material (FGM) was produced by vibration of W agglomerates in order to obtain the W skeleton with a gradient in porosity, which after pressureless sintering was infiltrated with molten Cu. Certain sintering mechanisms are suggested for these complex W structures. The segregation of two different sizes of W agglomerates was controlled by vibration time. Different vibration duration resulted in different types of microstructure: skeleton type microstructure after shorter vibration time and graded type microstructure after extended vibration times. The final Cu-infiltrated FGMs were characterized microstructurally and their electrical resistivity (r) was measured using the 4-probe technique. The values of r were in between those for pure W and Cu, depending strongly on the vibration times of the initial W agglomerates, and exhibiting particular r vs. T (K) behavior.