Mg-Ti基bcc结构固溶体的制备与性能研究

采用机械合金化制备Mg70-xTi12+xNi12Mn6(x=8、16、24、32)合金,通过X射线衍射(XRD)、差热分析(DTA)、扫描电子显微镜(SEM)和压强-成分-温度(PCT)分析等方法对合金粉末进行分析和表征。结果表明,随着球磨时间的增加,合金中hcp相所对应的衍射峰减弱,衍射峰宽化,合金中固溶度以及合金化程度提高;当球磨时间为200h时,在合金Mg46Ti36Ni12Mn6和Mg38Ti44Ni12Mn6中出现具有bcc结构的固溶体,Mg70-xTi12+xNi12Mn6(x=8、16、24、32)合金的吸氢量分别为0.83%、0.68%、1.36%和0.41%(质量分数),根据DTA测试结果,Mg70-xTi12+xNi12Mn6(x=8、16、24、32)合金氢化物的第一个吸热峰位置分别为670、688、593和662K。在Mg46Ti36Ni12Mn6合金中添加5%(质量分数)的TiF3和Nb2O5混合球磨后,合金的吸氢量分别增加到了2.33%和2.36%(质量分数),TiF3和Nb2O5能有效地提高Mg-Ti基合金的贮氢性能。

Preparation and property of Mg-Ti solid solution alloy with bcc structure

The Mg70-xTi12+xNi12Mn6(x=8,16,24,32) alloys were prepared by mechanical alloying,the structure and property were investigated by X-ray diffraction(XRD),differential thermal analysis(DTA),pressure-composition isotherm(PCT) and scanning electron microscope(SEM) measurements.The diffraction peaks of hcp structure were weaken and broaden,the solid solubility and the degree of amorphous increased with milling time.The bcc structure appeared in Mg46Ti36Ni12Mn6 and Mg38Ti44Ni12Mn6 alloy when milled 200h.The hydrogen storage capacity of Mg70-xTi12+xNi12Mn6(x=8,16,24,32) alloys was 0.83%,0.68%,1.36% and 0.41wt%,respectively.DTA results showed that the first endothermic peak of the alloys appeared at 670,688,593 and 662K.In order to improve the hydrogen storage property of the Mg46Ti36Ni12Mn6 alloy TiF3 and Nb2O5 were chosen as additive.For example,after the Mg46Ti36Ni12Mn6 as-mixed(without milling) powder +5wt%M(M=TiF3,Nb2O5) were milled 200h,the hydrogen storage capacity of Mg46Ti36Ni12Mn6+5wt%M(M=TiF3,Nb2O5) alloy reached 2.33wt% and 2.36wt%,respectively.TiF3 and Nb2O5 as additive could significantly improve the hydrogen storage capacity of Mg-Ti alloy.