The Mg-3.0Nd-0.2Zn-0.4Zr (NZ30K) alloys were prepared by direct-chill casting (DCC) and sand mould casting (SMC) processes,respectively and their microstructures and mechanical properties were investigated.The results...The Mg-3.0Nd-0.2Zn-0.4Zr (NZ30K) alloys were prepared by direct-chill casting (DCC) and sand mould casting (SMC) processes,respectively and their microstructures and mechanical properties were investigated.The results indicate that casting method plays a remarkable influence on the microstructure and mechanical properties of as-cast NZ30K alloy.The grain size increases from 35-40μm in the billets made by the DCC to about 100-120μm in the billets by the SMC.The aggregation of Mg12Nd usually found at the triple joints of grain boundaries in the billets prepared by SMC while is not observable from the billets by DCC.The tensile strengths and elongations of the billets are 195.2 MPa and 15.5% by DCC,and 162.5 MPa and 3.2% by SMC,respectively.The tensile strength of the alloy by DCC is remarkably enhanced by T6 heat treatment,which reached 308.5 MPa.Fracture surfaces of NZ30K alloy have been characterized as intergranular fracture by SMC and quasi-cleavage fracture by DCC,respectively.展开更多
This work aimed to analyze the glass material used for sealing the end of a thermal collector in a parabolic trough solar power plant. Based on matched sealing requirements and application performance of glass and Kov...This work aimed to analyze the glass material used for sealing the end of a thermal collector in a parabolic trough solar power plant. Based on matched sealing requirements and application performance of glass and Kovar alloy 4J29, one borosilicate glass material （GD480S）, whose expansion coefficient was similar to that of Kovar alloy 4J29, was studied. Moreover, the effect of the ratio of SiO2 to B203 on the glass properties was explored in detail by Fourier transform infrared spectroscopy. As the SiO2 to B203 ratio in the glass increased from 4.18 to 5.77, the expansion coefficient showed a decreasing trend from 4.95×10-6/℃ to 4.55℃ 10-6/℃. In addition, the water resistance performance improved, enabling the glass material to seal well with the alloy for application in a trough solar power plant. Thus, the increase in the SiO2 to B2O3 ratio made the glass structure more compact and improved the glass performance to meet the requirements of an industrial tubular receiver.展开更多
基金supported by the National High-tech R&D Program of China (863 Program),grant No.2009AA03Z521the foundation of Shanghai Rising-Star Program (A type),grant No. 09QA1403100
文摘The Mg-3.0Nd-0.2Zn-0.4Zr (NZ30K) alloys were prepared by direct-chill casting (DCC) and sand mould casting (SMC) processes,respectively and their microstructures and mechanical properties were investigated.The results indicate that casting method plays a remarkable influence on the microstructure and mechanical properties of as-cast NZ30K alloy.The grain size increases from 35-40μm in the billets made by the DCC to about 100-120μm in the billets by the SMC.The aggregation of Mg12Nd usually found at the triple joints of grain boundaries in the billets prepared by SMC while is not observable from the billets by DCC.The tensile strengths and elongations of the billets are 195.2 MPa and 15.5% by DCC,and 162.5 MPa and 3.2% by SMC,respectively.The tensile strength of the alloy by DCC is remarkably enhanced by T6 heat treatment,which reached 308.5 MPa.Fracture surfaces of NZ30K alloy have been characterized as intergranular fracture by SMC and quasi-cleavage fracture by DCC,respectively.
基金Funded by the Special Projects of Major Scientific and Technological Achievements of Hebei Province(No.13041110Z)
文摘This work aimed to analyze the glass material used for sealing the end of a thermal collector in a parabolic trough solar power plant. Based on matched sealing requirements and application performance of glass and Kovar alloy 4J29, one borosilicate glass material （GD480S）, whose expansion coefficient was similar to that of Kovar alloy 4J29, was studied. Moreover, the effect of the ratio of SiO2 to B203 on the glass properties was explored in detail by Fourier transform infrared spectroscopy. As the SiO2 to B203 ratio in the glass increased from 4.18 to 5.77, the expansion coefficient showed a decreasing trend from 4.95×10-6/℃ to 4.55℃ 10-6/℃. In addition, the water resistance performance improved, enabling the glass material to seal well with the alloy for application in a trough solar power plant. Thus, the increase in the SiO2 to B2O3 ratio made the glass structure more compact and improved the glass performance to meet the requirements of an industrial tubular receiver.
