The constituent of precipitations phases of aged melt-spun AlMgCu ribbons was characterized by high-resolution transmission electron microscopy and microhardness test. The cooling rate of as melt-spun ribbon was estim...The constituent of precipitations phases of aged melt-spun AlMgCu ribbons was characterized by high-resolution transmission electron microscopy and microhardness test. The cooling rate of as melt-spun ribbon was estimated to be 1.60×105 K/s from the empirical relation. The samples were aged at 200 ＆#176;C for 16 h after solution treatment. Two precipitation phases, i.e. Al2CuMg and abnormal amorphous SiO2 were identified in the T6 melt-spun AlMgCu ribbon. The crystal structure and stoichiometric composition of Al2CuMg phase are in good agreement with the reference results [WANG et al （2007; 2005）]. The combined experiments show that the formation of abnormal amorphous SiO2 appears to be associated with the higher cooling rate in melt-spinning process and has no significant effect on the peak hardness.展开更多
A partial substitution of Ni by Mn was implemented in order to improve the hydriding and dehydriding kinetics of the Mg2Ni-type alloys. The nanocrystalline and amorphous MgzNi-type Mg2Nil-xMnx （x=0, 0. 1, 0.2, 0.3, ...A partial substitution of Ni by Mn was implemented in order to improve the hydriding and dehydriding kinetics of the Mg2Ni-type alloys. The nanocrystalline and amorphous MgzNi-type Mg2Nil-xMnx （x=0, 0. 1, 0.2, 0.3, 0.4） alloys were synthesized by the melt-spinning technique. The structures of the as-cast and spun alloys were studied by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and high resolution transmission electron microscopy （HRTEM）. The hydrogen absorption and desorption kinetics of the alloys were measured with an automatically controlled Sieverts apparatus. The results show that the as-spun Mn-free alloy holds a typical nanocrystalline structure, whereas the as-spun alloys containing Mn display a nanocrystalline and amorphous structure, confirming that the substitution of Mn for Ni intensifies the glass forming ability of the Mg2Ni-type alloy. The hydrogen absorption and desorption capacities and kinetics of the alloys increase with increasing the spinning rate, for which the nanocrystalline and amorphous structure produced by the melt spinning is mainly responsible. The substitution of Mn for Ni evidently improves the hydrogen desorption performance. The hydrogen desorption capacities of the as-cast and spun alloys rise with the increase in the percentage of Mn substitution.展开更多
基金Project(42-QP-009)supported by Research Fund of the State Key Laboratory of Solidification Processing,ChinaProject(Z2012019)supported by Graduate Starting Seed Fund of Northwestern Polytechnical University,ChinaProject(B08040)supported by the Program of Introducing Talents of Discipline to Universities("111"Project),China
文摘The constituent of precipitations phases of aged melt-spun AlMgCu ribbons was characterized by high-resolution transmission electron microscopy and microhardness test. The cooling rate of as melt-spun ribbon was estimated to be 1.60×105 K/s from the empirical relation. The samples were aged at 200 ＆#176;C for 16 h after solution treatment. Two precipitation phases, i.e. Al2CuMg and abnormal amorphous SiO2 were identified in the T6 melt-spun AlMgCu ribbon. The crystal structure and stoichiometric composition of Al2CuMg phase are in good agreement with the reference results [WANG et al （2007; 2005）]. The combined experiments show that the formation of abnormal amorphous SiO2 appears to be associated with the higher cooling rate in melt-spinning process and has no significant effect on the peak hardness.
基金Projects(50871050,50961001) supported by the National Natural Science Foundation of ChinaProject(2010ZD05) supported by the Natural Science Foundation of Inner Mongolia,ChinaProject(NJzy08071) supported by the High Education Science Research Program of Inner Mongolia,China
文摘A partial substitution of Ni by Mn was implemented in order to improve the hydriding and dehydriding kinetics of the Mg2Ni-type alloys. The nanocrystalline and amorphous MgzNi-type Mg2Nil-xMnx （x=0, 0. 1, 0.2, 0.3, 0.4） alloys were synthesized by the melt-spinning technique. The structures of the as-cast and spun alloys were studied by X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and high resolution transmission electron microscopy （HRTEM）. The hydrogen absorption and desorption kinetics of the alloys were measured with an automatically controlled Sieverts apparatus. The results show that the as-spun Mn-free alloy holds a typical nanocrystalline structure, whereas the as-spun alloys containing Mn display a nanocrystalline and amorphous structure, confirming that the substitution of Mn for Ni intensifies the glass forming ability of the Mg2Ni-type alloy. The hydrogen absorption and desorption capacities and kinetics of the alloys increase with increasing the spinning rate, for which the nanocrystalline and amorphous structure produced by the melt spinning is mainly responsible. The substitution of Mn for Ni evidently improves the hydrogen desorption performance. The hydrogen desorption capacities of the as-cast and spun alloys rise with the increase in the percentage of Mn substitution.
