Mg−1Mn−0.5Al−0.5Ca−0.5Zn(wt.%)alloy was fabricated by conventional extrusion at 673 K with an extrusion ratio of 25:1,followed by aging at 473 K.The microstructure was characterized by scanning electron microscopy,ele...Mg−1Mn−0.5Al−0.5Ca−0.5Zn(wt.%)alloy was fabricated by conventional extrusion at 673 K with an extrusion ratio of 25:1,followed by aging at 473 K.The microstructure was characterized by scanning electron microscopy,electron back-scattered diffraction,and transmission electron microscopy.The mechanical properties were determined by the tensile test.The peak-aged sample shows fine recrystallized grains with an average grain size of 1.7μm.Area fraction of Al−Ca particles in the alloy increases significantly after peak aging.Meanwhile,botháañandác+añdislocations were observed to remain in the alloy after hot extrusion.Thus,the peak-aged sample exhibits simultaneously high strength and good ductility with the ultimate tensile stress,tensile yield stress,and tension fracture elongation of 320 MPa,314 MPa,and 19.0%,respectively.展开更多
The Gibbs free energy and critical reaction conditions of preparing Mg and Ca metal by carbothermic reducing calcined dolomite were calculated and analyzed.New thermodynamic criterion for reduction reaction,including ...The Gibbs free energy and critical reaction conditions of preparing Mg and Ca metal by carbothermic reducing calcined dolomite were calculated and analyzed.New thermodynamic criterion for reduction reaction,including the critical temperature and vacuum degree,was studied.The results show that:when T/P^(0.0449)<1199.2,neither MgO nor CaO can be reduced by carbon;when T/P^(0.0449)≥1199.2 and T/P^(0.0462)<1350.9,MgO can be reduced while CaO can not be;when T/P^(0.0462)≥1350.9,both MgO and CaO can be reduced.According to the requirements,we can obtain only Mg,Mg first then Ca,Mg and Ca simultaneously by controlling temperature,vacuum degree or both of them properly,by carbothermic reducing calcined dolomite.展开更多
基金the financial supports from the Fundamental Research Funds for the Central Universities,China(Nos.2019CDCGCL316,2020CDJDPT001)Chongqing Research Program of Basic Research and Frontier Technology,China(No.cstc2019jcjy-msxmX0539)。
文摘Mg−1Mn−0.5Al−0.5Ca−0.5Zn(wt.%)alloy was fabricated by conventional extrusion at 673 K with an extrusion ratio of 25:1,followed by aging at 473 K.The microstructure was characterized by scanning electron microscopy,electron back-scattered diffraction,and transmission electron microscopy.The mechanical properties were determined by the tensile test.The peak-aged sample shows fine recrystallized grains with an average grain size of 1.7μm.Area fraction of Al−Ca particles in the alloy increases significantly after peak aging.Meanwhile,botháañandác+añdislocations were observed to remain in the alloy after hot extrusion.Thus,the peak-aged sample exhibits simultaneously high strength and good ductility with the ultimate tensile stress,tensile yield stress,and tension fracture elongation of 320 MPa,314 MPa,and 19.0%,respectively.
基金appreciate the Ministry of Edu-cation of the People’s Republic of China and Chongqing University with National Undergraduates Innovating Experi-mentation Project 1210611007.
文摘The Gibbs free energy and critical reaction conditions of preparing Mg and Ca metal by carbothermic reducing calcined dolomite were calculated and analyzed.New thermodynamic criterion for reduction reaction,including the critical temperature and vacuum degree,was studied.The results show that:when T/P^(0.0449)<1199.2,neither MgO nor CaO can be reduced by carbon;when T/P^(0.0449)≥1199.2 and T/P^(0.0462)<1350.9,MgO can be reduced while CaO can not be;when T/P^(0.0462)≥1350.9,both MgO and CaO can be reduced.According to the requirements,we can obtain only Mg,Mg first then Ca,Mg and Ca simultaneously by controlling temperature,vacuum degree or both of them properly,by carbothermic reducing calcined dolomite.
