To address the challenges posed by high reaction temperatures and the slow kinetics of Mg-based alloys with high hydrogen storage density,Mg−RE−TM(RE=rare earth,TM=metallic element)alloys have been extensively researc...To address the challenges posed by high reaction temperatures and the slow kinetics of Mg-based alloys with high hydrogen storage density,Mg−RE−TM(RE=rare earth,TM=metallic element)alloys have been extensively researched and hold great promise.In this study,a series of Mg−RE−TM based Mg_(90)Y_(2)Ce_(2)Ni_(3)Al_(3-x)Sc_(x)(x=0,0.3,0.6,0.9,1.2)alloys were prepared.The addition of Sc element has been found to enhance the activation and kinetic properties of the alloy.Compared with the significant differences in the first four dehydrogenation curves of the Sc0 sample,the first activated dehydrogenation curve of the Sc1.2 alloy overlaps with the fully activated dehydrogenation curve.The dehydrogenation activation energy decreased from 96.56 kJ/mol in the Sc0 alloy to 63.69 kJ/mol in the Sc0.9 alloy.Through analysis of the microstructure,phase composition,and hydrogen absorption and desorption kinetics of the alloy,the mechanisms for improving the hydrogen storage properties of the alloy were elucidated.The nucleation-growth-impingement Avrami model was employed to accurately simulate the hydrogen storage kinetics.The results showed that stage II was prolonged and accelerated at high temperature,and the growth rate and hydrogen storage of stage I were increased at low temperature in hydrogen absorption.Microstructure analysis revealed the presence of Mg,CeMg_(12),Mg_(47)Y,and YNi_(2)Al_(3) phases in the Sc0 sample.Upon the addition of Sc element,a new phase,ScNiAl,was formed,and the coarse grain size of the main phase was significantly refined.This refinement provides faster diffusion channels for hydrogen atoms,accelerating the phase transition between Mg alloys and hydrides.The microstructure changes explain the improved activation properties,effective hydrogen absorption and desorption capacity,and kinetic properties of the Mg-based samples.展开更多
铸造耐热Al-Si-Cu-Ni-Mg合金是制备高功率密度发动机活塞等耐热轻量化部件的重要基础材料,通过添加高熔点、低热扩散系数的Sc元素来调控合金的相结构和形貌是提升此类合金耐温性的重要思路。因此,探究了Sc元素添加及其含量对铸造耐热Al-...铸造耐热Al-Si-Cu-Ni-Mg合金是制备高功率密度发动机活塞等耐热轻量化部件的重要基础材料,通过添加高熔点、低热扩散系数的Sc元素来调控合金的相结构和形貌是提升此类合金耐温性的重要思路。因此,探究了Sc元素添加及其含量对铸造耐热Al-Si-Cu-Ni-Mg活塞合金凝固组织和热暴露过程中富铜镍相组织演变的影响。结果表明,随Sc含量增加,活塞合金中形成Al Si CuNiSc新相,并且Al Si CuNiSc相的数量和尺寸随Sc含量的增加而增加;此外,随着Al Si CuNiSc相的形成,δ-Al_(3)CuNi相发生由典型共晶层片向棒杆状组织的转变。热暴露过程中,δ-Al_(3)CuNi相中的Cu和Ni原子向α-Al基体中扩散,并在δ-Al_(3)CuNi的相界面处形成纳米尺度的γ-Al_(7)Cu_(4)Ni相;而富Sc的Al Si CuNiSc相在热暴露前后形貌和成分几乎不发生变化,表现出极高的热稳定性;分析认为,高熔点、低热扩散系数的Si和Sc等原子在富铜镍相中的存在极大提高了富铜镍相的热稳定性。展开更多
基金National Natural Science Foundation of China(51871125)the Major Programs of Central Iron and Steel Research Institute(No.23020230ZD)for financial support of the work.
文摘To address the challenges posed by high reaction temperatures and the slow kinetics of Mg-based alloys with high hydrogen storage density,Mg−RE−TM(RE=rare earth,TM=metallic element)alloys have been extensively researched and hold great promise.In this study,a series of Mg−RE−TM based Mg_(90)Y_(2)Ce_(2)Ni_(3)Al_(3-x)Sc_(x)(x=0,0.3,0.6,0.9,1.2)alloys were prepared.The addition of Sc element has been found to enhance the activation and kinetic properties of the alloy.Compared with the significant differences in the first four dehydrogenation curves of the Sc0 sample,the first activated dehydrogenation curve of the Sc1.2 alloy overlaps with the fully activated dehydrogenation curve.The dehydrogenation activation energy decreased from 96.56 kJ/mol in the Sc0 alloy to 63.69 kJ/mol in the Sc0.9 alloy.Through analysis of the microstructure,phase composition,and hydrogen absorption and desorption kinetics of the alloy,the mechanisms for improving the hydrogen storage properties of the alloy were elucidated.The nucleation-growth-impingement Avrami model was employed to accurately simulate the hydrogen storage kinetics.The results showed that stage II was prolonged and accelerated at high temperature,and the growth rate and hydrogen storage of stage I were increased at low temperature in hydrogen absorption.Microstructure analysis revealed the presence of Mg,CeMg_(12),Mg_(47)Y,and YNi_(2)Al_(3) phases in the Sc0 sample.Upon the addition of Sc element,a new phase,ScNiAl,was formed,and the coarse grain size of the main phase was significantly refined.This refinement provides faster diffusion channels for hydrogen atoms,accelerating the phase transition between Mg alloys and hydrides.The microstructure changes explain the improved activation properties,effective hydrogen absorption and desorption capacity,and kinetic properties of the Mg-based samples.
文摘铸造耐热Al-Si-Cu-Ni-Mg合金是制备高功率密度发动机活塞等耐热轻量化部件的重要基础材料,通过添加高熔点、低热扩散系数的Sc元素来调控合金的相结构和形貌是提升此类合金耐温性的重要思路。因此,探究了Sc元素添加及其含量对铸造耐热Al-Si-Cu-Ni-Mg活塞合金凝固组织和热暴露过程中富铜镍相组织演变的影响。结果表明,随Sc含量增加,活塞合金中形成Al Si CuNiSc新相,并且Al Si CuNiSc相的数量和尺寸随Sc含量的增加而增加;此外,随着Al Si CuNiSc相的形成,δ-Al_(3)CuNi相发生由典型共晶层片向棒杆状组织的转变。热暴露过程中,δ-Al_(3)CuNi相中的Cu和Ni原子向α-Al基体中扩散,并在δ-Al_(3)CuNi的相界面处形成纳米尺度的γ-Al_(7)Cu_(4)Ni相;而富Sc的Al Si CuNiSc相在热暴露前后形貌和成分几乎不发生变化,表现出极高的热稳定性;分析认为,高熔点、低热扩散系数的Si和Sc等原子在富铜镍相中的存在极大提高了富铜镍相的热稳定性。
