Thermal stability and hydrogen absorption/desorption properties of Mg17Al12 produced by bulk mechanical alloying

摘要: Abstract We have demonstrated the synthesis of Mg17Al12, an inter-metallic compound, by both mechanical alloying (MA) based on high-energy ball milling, and bulk (BMA) repeated forging process. These two processing techniques resulted in alloys with different crystal structures. After MA up to 20 h, XRD peaks from Mg17Al12 un-alloyed Mg Al were observed. On other hand, elemental powders completely mechanically alloyed resulting after 2000 cycles BMA. (It should be emphasized that BMA correspond 4.4 h time.) Compared MA, has a great advantage time. From pressure–composition (P–C) isotherm powder at 523 K, plateau corresponding hydride formation clearly appeared 0.06 0.04 MPa during absorption desorption, respectively. It was confirmed alloy is able absorb hydrogen 3.2 wt.% 5.3 MPa, also desorb 523 K. When hydriding starts, decomposed into Mg2Al3 + MgH2 + Al. This reaction proceeds MgH2 + Al, as reported earlier. Then, these separated phases recombined phase upon de-hydriding.