W-Sn solid solution synthesized by mechanical alloying at room temperature

The structural evolution of the 5W-Sn mixtures during mechanical alloying (MA) using a planetary ball mill was systematically studied. The X-ray diffraction (XRD) patterns show that tin diffraction lines disappeared when the mixture was mechanically alloyed for a period longer than 20 h and no new second phase formed during MA. Based on the XRD data, the lattice parameter of the as-milled tungsten phase was analyzed by the Rietveld method using the Rietica software. The differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA) measurements show that the as-alloyed solid solution decomposed at 900 °C. The morphologies of the samples were observed using field emission scanning electron microscopy (FESEM). The XRD patterns of the 5W-Sn mixtures with different crystallite sizes obtained by computer simulation reveal that the mixture transformed into a solid solution rather than coherent composite or nanosized mechanocomposite during MA.