Magnesium and its alloys are widely recommended for automotive, electronics and biomedical industries due to their strength to weight ratio. The mechanically alloyed magnesium with Ni, Cu and Ca alloys exhibits superior properties. In this work, the ternary Mg70Ni10Ca20 and Mg85Cu10Ca5 alloys were synthesized by mechanical alloying for 10 h in SPEX mill with 10:1 ball to powder ratio under argon (Ar) atmosphere. Their structural and phase transformation with respect to milling time and composition were studied by X-ray diffraction (XRD), scanning electron microscopy and energy dispersive X-ray spectroscopy. The XRD pattern showed the formation of amorphous with nano crystalline peaks. The Mg2Cu and CaCu intermetallic phases were identified in Mg85Cu10Ca5 alloy and Mg2Ni and MgNi2 intermetallic compounds were identified in Mg70Ni10Ca20 alloy. A crystallite size of 44.45 nm was measured from alpha-Mg XRD peak in Mg-Cu-Ca alloy, and 45.59 nm was measured for the Mg2Ni phase in Mg-Ni-Ca alloy. (C) 2015 The Authors. Published by Elsevier Ltd.