The majority of industrial aluminum casting alloys exhibit low thermal conductivity,which is insufficient for effective heat transfer in electronic devices.The objective of this investigation was to develop new alumin...The majority of industrial aluminum casting alloys exhibit low thermal conductivity,which is insufficient for effective heat transfer in electronic devices.The objective of this investigation was to develop new aluminum casting alloys with high thermal conductivity.The impact of alloying elements on the thermal conductivity of pure aluminum was examined,and the relationships among microstructure,thermal conductivity,and the mechanical and corrosion properties of Al-Zn-Ca-(Cu,Mg)alloys were explored.The findings indicate that in the as-cast state,the structure of the alloys consists ofα-Al and a eutectic containing the(Al,Zn)4Ca phase.Following the solution heat treatment,the(Al,Zn)4Ca phase is spheroidised,and thermal conductivity of the alloys increases,reaching over 75%that of pure aluminum.However,the heat-treated alloys exhibit low mechanical properties:tensile yield strength<60 MPa,ultimate tensile strength<160 MPa,and elongation at fracture>15%.The alloys demonstrate satisfactory fluidity and low hot tearing susceptibility.With the exception of the alloy containing copper,the alloys exhibit low corrosion rates,estimated at approximately 0.02 mm/a.展开更多
Magnesium alloys are used in aircraft because of their light weight.However,for these alloys to be applied in electronic devices,high thermal conductivities are required.Several high-potential compositions of Mg-Zn-Y-...Magnesium alloys are used in aircraft because of their light weight.However,for these alloys to be applied in electronic devices,high thermal conductivities are required.Several high-potential compositions of Mg-Zn-Y-Zr alloys were selected by phase composition and their freezing ranges calculated using Thermo-Calc software.The alloys were prepared,and their fluidity,hot tearing susceptibility,mechanical properties,and thermal conductivity were obtained and compared.The alloy composed of Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr was selected for further investigation,because of its high thermal conductivity and satisfactory mechanical properties.The Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr alloy’s fluidity and hot tearing susceptibility were similar to those of the widespread AZ91 commercial casting magnesium alloy.The influence of a heat treatment regime on the microstructure,thermal conductivity,and mechanical properties of the developed alloy was also investigated.It was established that the room temperature thermal conductivity of the Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr alloy after aging at 300℃for 5 h was 105 W/m K^(-1).Additionally,the following tensile test results were obtained in aged condition:120 MPa yield strength,200 MPa ultimate tensile strength,and 4%elongation.The utilization of solid solution heat treatment at 520℃for 8 h prior to aging can promote up to 9%increase in elongation.The Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr casting alloy can be used as a high thermal conductivity material with industrial applications.展开更多
基金supported by the Russian Science Foundation(No.24-29-00682,https://rscf.ru/project/24-29-00682/).
文摘The majority of industrial aluminum casting alloys exhibit low thermal conductivity,which is insufficient for effective heat transfer in electronic devices.The objective of this investigation was to develop new aluminum casting alloys with high thermal conductivity.The impact of alloying elements on the thermal conductivity of pure aluminum was examined,and the relationships among microstructure,thermal conductivity,and the mechanical and corrosion properties of Al-Zn-Ca-(Cu,Mg)alloys were explored.The findings indicate that in the as-cast state,the structure of the alloys consists ofα-Al and a eutectic containing the(Al,Zn)4Ca phase.Following the solution heat treatment,the(Al,Zn)4Ca phase is spheroidised,and thermal conductivity of the alloys increases,reaching over 75%that of pure aluminum.However,the heat-treated alloys exhibit low mechanical properties:tensile yield strength<60 MPa,ultimate tensile strength<160 MPa,and elongation at fracture>15%.The alloys demonstrate satisfactory fluidity and low hot tearing susceptibility.With the exception of the alloy containing copper,the alloys exhibit low corrosion rates,estimated at approximately 0.02 mm/a.
文摘Magnesium alloys are used in aircraft because of their light weight.However,for these alloys to be applied in electronic devices,high thermal conductivities are required.Several high-potential compositions of Mg-Zn-Y-Zr alloys were selected by phase composition and their freezing ranges calculated using Thermo-Calc software.The alloys were prepared,and their fluidity,hot tearing susceptibility,mechanical properties,and thermal conductivity were obtained and compared.The alloy composed of Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr was selected for further investigation,because of its high thermal conductivity and satisfactory mechanical properties.The Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr alloy’s fluidity and hot tearing susceptibility were similar to those of the widespread AZ91 commercial casting magnesium alloy.The influence of a heat treatment regime on the microstructure,thermal conductivity,and mechanical properties of the developed alloy was also investigated.It was established that the room temperature thermal conductivity of the Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr alloy after aging at 300℃for 5 h was 105 W/m K^(-1).Additionally,the following tensile test results were obtained in aged condition:120 MPa yield strength,200 MPa ultimate tensile strength,and 4%elongation.The utilization of solid solution heat treatment at 520℃for 8 h prior to aging can promote up to 9%increase in elongation.The Mg-4 wt%Zn-3 wt%Y-0.3 wt%Zr casting alloy can be used as a high thermal conductivity material with industrial applications.
