In the fabrication of W-Cu nanocomposite powders, it is important to consider the design of the alloying content and microstructure to get optimal thermal properties. However, W and Cu have mutual insolubility and their contact angle is very large, thus it is difficult to fabricate homogeneous and fully dense composite materials. Therefore, in recent years studies have been made of the fabrication of W-Cu nanocomposites through the reduction of WO3-CuO powders. In the present study, WO3 and CuO powders were ball-milled with high energy at 400 rpm for 1-50h in Ar atmosphere. They were examined using XRD, SEM and TEM. After the sieved WO3-CuO powders were reduced in dry hydrogen, the reduced W-Cu powders were liquidphase sintered at 1200 and 1300oC for 1h in dry hydrogen. After ball-milling of 1h, the reduced powder had a cored structure and the W particles were faceted. However, after ball-milling of 20h, the powder had a "homogeneously mixed structure" and the W particles were smaller than from the reduced powder ball-milled for 1h. After sintering at 1200oC, the W grain size was finest and most homogeneous with 20h of milling time and a reduction treatment at 980oC.

Keywords: W-Cu composite, nanocomposite, mechanical alloying, high energy ball milling, reduction, liquid phase sintering, mechano chemical process