Aluminium-copper hybrid parts, as a substitution to copper parts, result in weight and cost reduction, and are relevant in applications related to the electronic, heating and cooling sector. However, aluminium to copp...Aluminium-copper hybrid parts, as a substitution to copper parts, result in weight and cost reduction, and are relevant in applications related to the electronic, heating and cooling sector. However, aluminium to copper joined by thermal welding processes presents challenges in terms of achieving good joint quality. This is attributed to their dissimilar mechanical and thermal properties which result in large stress gradients during heating. This study investigated joining of aluminium to copper sheets by electromagnetic pulse welding, which is a solid-state process that uses electromagnetic forces for joining of dissimilar materials. Hybrid sheet welds were obtained for all parameters conditions, selected according to a Taguchi L18 design. The structural and mechanical characteristics were examined and related to the welding parameters by means of a Pareto analysis and response graphs. The welded zone started with a wavy interface with interfacial layers and defects and evolved to a flat interface without interfacial layers. The maximum transferable force depended on the minimum specimen thickness and the strength of the hybrid sheet weld. In case of aluminium sheet thickness reduction, the maximum transferable force was linearly correlated with the aluminium sheet thickness. High quality joints were obtained for no aluminium sheet thickness reduction and for a sheet weld strength which was at least as high as that of the base material. The most effective way to increase the transferable force was to lower the initial gap and to increase the free length, which resulted in no aluminium sheet thickness reduction. Alternatively, the use of a rounded spacer decreased the effect of the aluminium sheet thickness on the transferable force. An increase in weld width was achieved for an increase in capacitor charging energy and gap, whereas an increase in weld length was obtained for a decrease in gap. An increase in weld width did not necessarily result in an increase in the transferable force. In the regarded cases, a hybrid sheet with narrow weld width could therefore have higher quality.展开更多
Copper welding with an infrared(IR)Gaussian laser beam usually shows obvious instability,spatters,and worse surface morphology due to the Gaussian distribution,temperature-dependent IR absorption,and high thermal cond...Copper welding with an infrared(IR)Gaussian laser beam usually shows obvious instability,spatters,and worse surface morphology due to the Gaussian distribution,temperature-dependent IR absorption,and high thermal conductivity in cop-per.In this paper,the IR quasi-continuous-wave Gaussian beam was converted into a vortex ring beam with a phase-plate and then applied to the micro-spot-welding of copper sheets.The welding with the vortex beam demonstrated a significantly improved welding performance,smoother surface morphology,and higher welding stability.Besides,no spatters appeared in the welding process.展开更多
对七道次异步叠轧铜板采用220℃×30 m in和220℃×40 m in两种工艺进行退火,运用背散射电子衍射技术对两种铜板的再结晶程度、织构和晶界特征分布进行了研究。结果表明,经220℃×40 m in退火处理后,铜板的再结晶较完全,其...对七道次异步叠轧铜板采用220℃×30 m in和220℃×40 m in两种工艺进行退火,运用背散射电子衍射技术对两种铜板的再结晶程度、织构和晶界特征分布进行了研究。结果表明,经220℃×40 m in退火处理后,铜板的再结晶较完全,其织构为明显的{100}〈001〉立方织构;而经220℃×30 m in退火处理后,铜板内仍存在晶体缺陷,其织构为{123}〈412〉轧制织构及少量的{100}〈001〉立方织构。晶界特征分布图表明晶界都主要分布在Σ1、Σ3、Σ7、Σ9和Σ11位置上,采用220℃×40 m in退火处理后铜板中各主要晶界的含量明显高于采用220℃×30m in退火后的。展开更多
文摘Aluminium-copper hybrid parts, as a substitution to copper parts, result in weight and cost reduction, and are relevant in applications related to the electronic, heating and cooling sector. However, aluminium to copper joined by thermal welding processes presents challenges in terms of achieving good joint quality. This is attributed to their dissimilar mechanical and thermal properties which result in large stress gradients during heating. This study investigated joining of aluminium to copper sheets by electromagnetic pulse welding, which is a solid-state process that uses electromagnetic forces for joining of dissimilar materials. Hybrid sheet welds were obtained for all parameters conditions, selected according to a Taguchi L18 design. The structural and mechanical characteristics were examined and related to the welding parameters by means of a Pareto analysis and response graphs. The welded zone started with a wavy interface with interfacial layers and defects and evolved to a flat interface without interfacial layers. The maximum transferable force depended on the minimum specimen thickness and the strength of the hybrid sheet weld. In case of aluminium sheet thickness reduction, the maximum transferable force was linearly correlated with the aluminium sheet thickness. High quality joints were obtained for no aluminium sheet thickness reduction and for a sheet weld strength which was at least as high as that of the base material. The most effective way to increase the transferable force was to lower the initial gap and to increase the free length, which resulted in no aluminium sheet thickness reduction. Alternatively, the use of a rounded spacer decreased the effect of the aluminium sheet thickness on the transferable force. An increase in weld width was achieved for an increase in capacitor charging energy and gap, whereas an increase in weld length was obtained for a decrease in gap. An increase in weld width did not necessarily result in an increase in the transferable force. In the regarded cases, a hybrid sheet with narrow weld width could therefore have higher quality.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(No.61775153)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)Major Science and Technology Project of Hubei Province(No.2020AAA003).
文摘Copper welding with an infrared(IR)Gaussian laser beam usually shows obvious instability,spatters,and worse surface morphology due to the Gaussian distribution,temperature-dependent IR absorption,and high thermal conductivity in cop-per.In this paper,the IR quasi-continuous-wave Gaussian beam was converted into a vortex ring beam with a phase-plate and then applied to the micro-spot-welding of copper sheets.The welding with the vortex beam demonstrated a significantly improved welding performance,smoother surface morphology,and higher welding stability.Besides,no spatters appeared in the welding process.
文摘对七道次异步叠轧铜板采用220℃×30 m in和220℃×40 m in两种工艺进行退火,运用背散射电子衍射技术对两种铜板的再结晶程度、织构和晶界特征分布进行了研究。结果表明,经220℃×40 m in退火处理后,铜板的再结晶较完全,其织构为明显的{100}〈001〉立方织构;而经220℃×30 m in退火处理后,铜板内仍存在晶体缺陷,其织构为{123}〈412〉轧制织构及少量的{100}〈001〉立方织构。晶界特征分布图表明晶界都主要分布在Σ1、Σ3、Σ7、Σ9和Σ11位置上,采用220℃×40 m in退火处理后铜板中各主要晶界的含量明显高于采用220℃×30m in退火后的。
