随着高工作温度红外光电子器件的发展,更高的工作温度下,冷屏部件的热辐射会带来背景辐射噪声,对红外探测器的成像造成干扰。为研究高温器件冷屏部件热辐射对芯片性能的影响,基于蒙特卡洛原理,采用3D Studio Max建立冷屏模型,提取模型...随着高工作温度红外光电子器件的发展,更高的工作温度下,冷屏部件的热辐射会带来背景辐射噪声,对红外探测器的成像造成干扰。为研究高温器件冷屏部件热辐射对芯片性能的影响,基于蒙特卡洛原理,采用3D Studio Max建立冷屏模型,提取模型信息编写程序,计算冷屏部件各部分对芯片的辐射传递因子,进而得到冷屏部件热辐射在芯片上产生的噪声信号。在给定的参数和条件下,对某高温器件冷屏进行计算分析,表明该高温器件冷屏部件的温度需低于196 K。为抑制高温器件冷屏部件的热辐射,研究了整体降低冷屏发射率和局部降低冷屏发射率这两种方案。整体降低冷屏发射率可降低冷屏自身热辐射产生的噪声信号,但会造成外部辐射中经冷屏反射间接到达芯片的杂散辐射噪声信号迅速增加。局部降低冷屏发射率可降低冷屏自身热辐射产生的噪声信号并使外部辐射中经冷屏反射间接到达芯片的杂散辐射噪声信号缓慢增加。采用局部降低冷屏发射率的方案,对总的杂散辐射的抑制效果与温度有关,当冷屏部件温度小于203 K时,会引起总的杂散辐射噪声信号增加;当冷屏部件温度大于203 K时,可以降低总的杂散辐射噪声信号。展开更多
High-entropy alloy composites(HEACs)have attracted significant attention due to their exceptional mechanical properties and chemical stability.By adjusting the content of reinforcing particles in the high-entropy allo...High-entropy alloy composites(HEACs)have attracted significant attention due to their exceptional mechanical properties and chemical stability.By adjusting the content of reinforcing particles in the high-entropy alloy and by employing advanced additive manufacturing techniques,high-performance HEACs can be fabricated.However,there is still considerable room for improvement in their performance.In this study,CoCrFeMnNi HEA powders were used as the matrix,and NiCoFeAlTi high-entropy intermetallic powders were used as the high-entropy reinforcement(HER).CoCrFeMnNi/NiCoFeAlTi HEACs were fabricated using selective laser melting technology.The study results indicate that after aging,the microstructure of HEACs with HER exhibits Al-and Ti-rich nano-oxide precipitates with an orthorhombic CMCM type structure system.After aging at 873 K for 2 h,HEACs with HER achieved excellent overall mechanical properties,with an ultimate tensile strength of 731 MPa.This is attributed to the combined and synergistic effects of precipitation strengthening,dislocation strengthening,and the high lattice distortion caused by high intragranular defects,which provide a multi-scale strengthening and hardening mechanism for the plastic deformation of HEACs with HER.This study demonstrates that aging plays a crucial role in controlling the precipitate phases in complex multi-element alloys.展开更多
基金Project supported by ClassⅢPeak Discipline of Shanghai-Materials Science and Engineering(High-Energy Beam Intelligent Processing and Green Manufacturing),China。
文摘High-entropy alloy composites(HEACs)have attracted significant attention due to their exceptional mechanical properties and chemical stability.By adjusting the content of reinforcing particles in the high-entropy alloy and by employing advanced additive manufacturing techniques,high-performance HEACs can be fabricated.However,there is still considerable room for improvement in their performance.In this study,CoCrFeMnNi HEA powders were used as the matrix,and NiCoFeAlTi high-entropy intermetallic powders were used as the high-entropy reinforcement(HER).CoCrFeMnNi/NiCoFeAlTi HEACs were fabricated using selective laser melting technology.The study results indicate that after aging,the microstructure of HEACs with HER exhibits Al-and Ti-rich nano-oxide precipitates with an orthorhombic CMCM type structure system.After aging at 873 K for 2 h,HEACs with HER achieved excellent overall mechanical properties,with an ultimate tensile strength of 731 MPa.This is attributed to the combined and synergistic effects of precipitation strengthening,dislocation strengthening,and the high lattice distortion caused by high intragranular defects,which provide a multi-scale strengthening and hardening mechanism for the plastic deformation of HEACs with HER.This study demonstrates that aging plays a crucial role in controlling the precipitate phases in complex multi-element alloys.
