Dissimilar metals TIG welding-brazing of aluminum alloy and non-coated stainless steel was investigated. The resultant joint was characterized in order to identify the phases and the brittle intermetallic compounds （...Dissimilar metals TIG welding-brazing of aluminum alloy and non-coated stainless steel was investigated. The resultant joint was characterized in order to identify the phases and the brittle intermetallic compounds （IMCs） in the interracial layer by optical metalloscope （OM）, scanning electron microscopy （SEM） and energy dispersive spectrometer （ EDS） , and the cracked joint was analyzed in order to understand the cracking mechanism of the joint. The results show that the microfusion of the stainless steel can improve the wetting and spreading of liquid aluminum base filler metal on the steel suuface and the melted steel accelerates the formation of mass of brittle IMCs in the interracial layer, which causes the joint cracking badly. The whole interfacial layer is 5 -7 μm thick and comprises approximately 5μm-thickness reaction layer in aluminum side and about 2 μm-thickness diffusion layer in steel side. The stable Al-rich IMCs are formed in the interfacial layer and the phases transfer from （ Al ＋ FeAl3 ） in aluminum side to （ FeAl3 ＋ Fe2Al5 ） and （ α-Fe ＋ FeAl） in steel side.展开更多
Yield forecasting can give early warning of food risks and provide solid support for food security planning.Climate change and land use change have direct influence on regional yield and planting area of maize,but few...Yield forecasting can give early warning of food risks and provide solid support for food security planning.Climate change and land use change have direct influence on regional yield and planting area of maize,but few studies have examined their synergistic impact on maize production.In this study,we propose an analysis framework based on the integration of system dynamic(SD),future land use simulation(FLUS)and a statistical crop model to prefuture maize yield variation in response to climate change and land use change in a region of central Jilin province,China.The results show that the cultivated land is likely to reduce by 862.84 km^(2) from 2030 to 2050.Nevertheless,the total maize yield is expected to increase under all four RCP scenarios due to the promotion of per hectare maize yield.the scenarios,RCP4.5 is the most beneficial to maize production,with a doubled total yield in 2050.Notably,the yield gap between different counties will be further widened,which necessitates the differentiated policies of agricultural production and farmland protection,e.g.,strengthening cultivated land protection and crop management in low-yield areas,and taking adaptation and mitigation measures to coordinate climate change and production.展开更多
基金Supported by National Natural Science Foundation of China （50874033）.
文摘Dissimilar metals TIG welding-brazing of aluminum alloy and non-coated stainless steel was investigated. The resultant joint was characterized in order to identify the phases and the brittle intermetallic compounds （IMCs） in the interracial layer by optical metalloscope （OM）, scanning electron microscopy （SEM） and energy dispersive spectrometer （ EDS） , and the cracked joint was analyzed in order to understand the cracking mechanism of the joint. The results show that the microfusion of the stainless steel can improve the wetting and spreading of liquid aluminum base filler metal on the steel suuface and the melted steel accelerates the formation of mass of brittle IMCs in the interracial layer, which causes the joint cracking badly. The whole interfacial layer is 5 -7 μm thick and comprises approximately 5μm-thickness reaction layer in aluminum side and about 2 μm-thickness diffusion layer in steel side. The stable Al-rich IMCs are formed in the interfacial layer and the phases transfer from （ Al ＋ FeAl3 ） in aluminum side to （ FeAl3 ＋ Fe2Al5 ） and （ α-Fe ＋ FeAl） in steel side.
基金National Natural Science Foundation of China,No.42171414,No.41771429The Open Fund of Key Laboratory for Synergistic Prevention of Water and Soil Environmental Pollution,No.KLSPWSEP-A02。
文摘Yield forecasting can give early warning of food risks and provide solid support for food security planning.Climate change and land use change have direct influence on regional yield and planting area of maize,but few studies have examined their synergistic impact on maize production.In this study,we propose an analysis framework based on the integration of system dynamic(SD),future land use simulation(FLUS)and a statistical crop model to prefuture maize yield variation in response to climate change and land use change in a region of central Jilin province,China.The results show that the cultivated land is likely to reduce by 862.84 km^(2) from 2030 to 2050.Nevertheless,the total maize yield is expected to increase under all four RCP scenarios due to the promotion of per hectare maize yield.the scenarios,RCP4.5 is the most beneficial to maize production,with a doubled total yield in 2050.Notably,the yield gap between different counties will be further widened,which necessitates the differentiated policies of agricultural production and farmland protection,e.g.,strengthening cultivated land protection and crop management in low-yield areas,and taking adaptation and mitigation measures to coordinate climate change and production.
