Synthesis of Mg2Ni alloy by bulk mechanical alloying

Mg2Ni was synthesized by a solid-state reaction from the constituent elemental powder mixtures via bulk mechanical alloying. Since homogeneous refining and alloying takes place efficiently by repeated forging, the process time can be reduced to one fiftieth of time duration necessary for conventional mechanical milling and attrition. This MA Mg2Ni alloy can be obtained as a high dense powder compact with a relative mass density in the order of 85%; its average powder particle size ranges from 1 to 3 mu m The prepared Mg2Ni alloy has a sufficiently high reaction rate to hydrogen even at relatively lower temperatures and a potential to form a ternary hydride on the pressure-composition isotherms from 523 to 623 K. The enthalpy and entropy for ternary hydride formation were estimated to be -28. 7 KJ/mole-H and -46. 8 J/K/mole-H, respectively. The present bulk mechanical alloying was found to be adaptive to fabrication of single phase Mg2Ni in high productivity. (C) 1999 Elsevier Science S.A. All rights reserved.