ZK60 Nanocrystalline Magnesium Alloy Powder Prepared by Hydrogenation-dehydrogenation and Their Microstructure Evolution

A new technology to manufacture nanocrystalline materials of ZK60 alloy powder was developed via studying the influence of hydrogenation temperature, hydrogen pressure and reaction time of the HDDR (hydrogenation-disproportionation-desorption- recombination) process on the course of hydrogen-desorption by XRD, OM, SEM and TEM. The microstructural evolution of the alloy powder was researched. Results show that the temperature plays an important role in the hydrogen-desorption process of ZK60 alloy. The optimal HD process for preparing nanocrystalline Mg alloy powders is that the alloy is hydrogenated at 350 degrees C under 2 MPa hydrogen pressure for 12 h and then dehydrogenated at 350 degrees C for 3 h in vacuum. The grain sizes of ZK60 alloy are refined to about 20 nm from 160 mu m.