Synthesis of Mg2Ni alloy by bulk mechanical alloying

Mg2Ni was synthesized by a solid-state reaction from the constituent elemen tal powder mixtures via bulk mechanical alloying. Since homogeneous refinin g and alloying takes place efficiently by repeated forging, the process tim e can be reduced to one fiftieth of time duration necessary for conventiona l 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 Mg 2Ni alloy has a sufficiently high reaction rate to hydrogen even at relativ ely lower temperatures and a potential to form a ternary hydride on the pre ssure-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 t o be adaptive to fabrication of single phase Mg2Ni in high productivity. (C ) 1999 Elsevier Science S.A. All rights reserved.