A novel approach to fabricate W-Cu functionally graded materials via sedimentation and infiltration method

In this paper, W-Cu functionally graded materials (W-Cu FGMs) with continuously gradient distribution of W (Cu) composition and microstructure was fabricated by a novel method of sedimentation and melt-infiltration. Sedimentation behavior of W particles in the suspension and influence of the suspension composition on the microstructure and properties of the W-Cu FGMs was investigated. The results indicate that W-Cu FGMs with continuously gradient distribution of W(Cu) content along the cross section can be successfully obtained by the above sedimentation and infiltration method. The addition of an appropriate amount of PVB in the suspension can expand the gradient distribution range of W-Cu FGMs. With the suspension containing 4% PVB, the content of Cu in the prepared W-Cu FGMs changes from 28.03% in the lower Cu layer to 44.47% in the higher Cu layer. Corresponding to the compositional changes, the hardness in the W-Cu FGMs changes from 175.32 HV in the lower Cu layer to 108.62 HV in the higher Cu layer, and the density, thermal conductivity, and electrical conductivity of the overall W-Cu FGMs are 98.23%, 285 W/(m K) and 58.3 IACS, respectively. The present work provides an effective method for preparing W-Cu FGMs with continuously gradient distribution of composition and excellent performance.