In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx （x=0.2, 0.4, 0.6, 0.8） solid solutions, microwave irradiation techniques were used in pr...In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx （x=0.2, 0.4, 0.6, 0.8） solid solutions, microwave irradiation techniques were used in preparing them as thermoelectric materials. Structure and phase composition of the obtained materials were investigated by X-ray diffraction （XRD）. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature from 300 to 750 K. It is found that Mg2Si1-xSnx solid solutions are well formed with excessive content of 5% （molar fraction） Mg from the stoichiometric MgESil.xSnx under microwave irradiation. A maximum dimensionless figure of merit, ZT, of about 0.26 is obtained for Mg2Si1-xSnx solid solutions at about 500 K for x=0.6.展开更多
In this paper, high-zirconium Zr66＋2xAl9-x（Ni1/3Cu2/3）25-x （x=0,1,2 at.%） bulk metallic glasses with high strength and large duc- tility were fabricated by copper mould casting. The effects of zirconium content o...In this paper, high-zirconium Zr66＋2xAl9-x（Ni1/3Cu2/3）25-x （x=0,1,2 at.%） bulk metallic glasses with high strength and large duc- tility were fabricated by copper mould casting. The effects of zirconium content on the glass-forming ability （GFA）, thermal properties and mechanical properties were investigated using X-ray diffractometer （XRD）, differential scanning calorimeter （DSC）, and mechanical testing system in compressive and three-point bending modes, respectively. The high-zirconium BMGs show the critical diameters of 3-5 ram, the supercooled liquid region ranging from 70 K to 99 K, and the yield strength of over 1700 MPa. The Zr70Al7（Ni1/3Cu2/3）23 BMG exhibits a large compressive plastic strain up to 21% and a high notch toughness value of 60.6 MPa m1/2. The increase in Zr content results in the decrease in GFA and thermostability, and in the improvement of plasticity under compressive and three-point bending conditions. The superior plasticity of high-zirconium BMGs is at- tributed to their high Poisson＇s ratio and small elastic modulus ratioμl/B.展开更多
基金Project(2009BB4228) supported by the Natural Science Foundation of Chongqing City,ChinaProject(CK2010Z09) supported by the Research Foundation of Chongqing University of Science and Technology,China
文摘In order to reduce the oxidizing and volatilizing caused by Mg element in the traditional methods for synthesizing Mg2Sil-xSnx （x=0.2, 0.4, 0.6, 0.8） solid solutions, microwave irradiation techniques were used in preparing them as thermoelectric materials. Structure and phase composition of the obtained materials were investigated by X-ray diffraction （XRD）. The electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature from 300 to 750 K. It is found that Mg2Si1-xSnx solid solutions are well formed with excessive content of 5% （molar fraction） Mg from the stoichiometric MgESil.xSnx under microwave irradiation. A maximum dimensionless figure of merit, ZT, of about 0.26 is obtained for Mg2Si1-xSnx solid solutions at about 500 K for x=0.6.
文摘In this paper, high-zirconium Zr66＋2xAl9-x（Ni1/3Cu2/3）25-x （x=0,1,2 at.%） bulk metallic glasses with high strength and large duc- tility were fabricated by copper mould casting. The effects of zirconium content on the glass-forming ability （GFA）, thermal properties and mechanical properties were investigated using X-ray diffractometer （XRD）, differential scanning calorimeter （DSC）, and mechanical testing system in compressive and three-point bending modes, respectively. The high-zirconium BMGs show the critical diameters of 3-5 ram, the supercooled liquid region ranging from 70 K to 99 K, and the yield strength of over 1700 MPa. The Zr70Al7（Ni1/3Cu2/3）23 BMG exhibits a large compressive plastic strain up to 21% and a high notch toughness value of 60.6 MPa m1/2. The increase in Zr content results in the decrease in GFA and thermostability, and in the improvement of plasticity under compressive and three-point bending conditions. The superior plasticity of high-zirconium BMGs is at- tributed to their high Poisson＇s ratio and small elastic modulus ratioμl/B.
