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为了探究La0.62Y0.2Mg0.18Ni3.30Al0.20合金具有良好气态吸放氢性能的适宜退火温度,采用XRD、OM分析了铸态及退火合金的相结构及金相组织,用SEM观察了吸放氢前后合金颗粒的表面形貌,用压力-组成-温度(PCT)仪测试了合金的PCT特性以及吸放氢动力学性能。结果表明,900℃退火合金含有LaNi5和(La,Y,Mg)2(Ni,Al)7主相以及Ni3Y残余相。随着退火温度升高,主相不变,但Ni3Y转变成Y2Ni7相;主相晶胞体积先增大后减小,在41~43°衍射角度内,半高宽先减小后增大。与铸态及其他温度退火合金相比,950℃退火合金的组织均匀性较好,吸放氢量、平均吸放氢速率较高,吸放氢的氢压和滞后系数较小。综合比较,实验范围内,合金的适宜退火温度为950℃。
In order to investigate the suitable annealing temperature of La0.62Y0.2Mg0.18Ni3.30Al0.20 alloy, the phase structure and microstructure of as-cast and annealed alloys were analyzed by XRD and OM. The adsorption of The surface morphology of the alloy particles before and after hydrogen releasing was tested. The PCT characteristics and hydrogen absorption and desorption kinetics of the alloy were tested by pressure - composition - temperature (PCT). The results show that the 900 ℃ annealed alloy contains LaNi5 and (La, Y, Mg) 2 (Ni, Al) 7 main phases and Ni3Y residual phases. With the increase of annealing temperature, the main phase does not change, but Ni3Y is transformed into Y2Ni7 phase. The volume of the main phase unit first increases and then decreases, and the FWHM decreases firstly and then increases in the angle of 41 ~ 43 °. Compared with the as-cast and other temperature-annealed alloys, the microstructure of the alloy annealed at 950 ℃ is better, the hydrogen absorption and desorption capacity is higher, the average rate of hydrogen absorption and desorption is higher, and the hydrogen pressure and the retardation coefficient of hydrogen absorption and desorption are smaller. Comprehensive comparison, the experimental range, the appropriate annealing temperature alloy 950 ℃.