It is well known that mechanical alloying (MA) could form non-equilibrium materials such as super-saturated solid solution, nanocrystalline and amorphous materials even in immiscible systems with the positive heat of mixing. However, few structural studies have been performed for both the ternary and immiscible system until now. In this study, MA of W-Cu-Pb powder mixture was performed at room temperature (RT) and ― 100°C in order to investigate the possibility of forming metastable phase in immiscible ternary system as well as the milling temperature effect on the extent of alloying. The MAed W-Cu-Pb powder was characterized by using X-ray diffraction(XRD), field emission-scanning electron microscopy(FE-SEM), transmission electron microscopy(TEM) and extended X-ray absorption fine structure(EXAFS). The final structure of W-Cu-Pb powder milled at RT was found to be a mixture of nanocrystalline W, Cu and Pb with the particle size below about 30 nm. The high energy ball milling at low temperature of ― 100°C caused the further particle size refinement and remarkably enhanced the amorphization reaction between W, Cu and Pb despite their mutual non-solubility. A very significant amorphization occurred after milling for 150 h. This is believed to be attributed to the full suppression of the atomic mobility responsible for phase separation when the milling was conducted at ― 100°C.
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