Abstract In this study, a direct diffusion bonding method is designed to bond tungsten (W) and copper (Cu) without using an interlayer metal at a temperature close to the melting point of copper (TmCu). The results show that the direct diffusion bonding method is feasible and the key point to a successful connection is that bonding temperatures should be controlled in an effective temperature range 0.81TmCu–0.97TmCu. The most appropriate bonding parameters are that the bonding temperature is 980 °C, the bonding time is 180 min and the bonding pressure is 106 MPa. The maximum tensile and bending strengths of the as-obtained W/Cu joints are ~ 172 and ~ 232 MPa, respectively, which reach a very high level compared to pure copper. The corresponding fractures are ductile. The micro-tests for the W/Cu joint show that diffusion occurs between W and Cu and the thickness of the W/Cu diffusion layer is ~ 22 nm. Through the diffusion, a metallurgical bonding interface has been successfully constructed, which is the essential reason for the high strengths of the W/Cu joint. The diffusion between W and Cu when the bonding temperature is close to TmCu may be induced by the high-temperature structure of Cu, which needs further investigation.

中文翻译：

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不混溶的钨和铜在接近铜熔点的温度下直接扩散键合

摘要 在本研究中，设计了一种直接扩散键合方法，在接近铜 (TmCu) 熔点的温度下不使用层间金属键合钨 (W) 和铜 (Cu)。结果表明，直接扩散键合方法是可行的，连接成功的关键是键合温度应控制在有效温度范围 0.81TmCu–0.97TmCu 内。最合适的键合参数是键合温度为980°C，键合时间为180 min，键合压力为106 MPa。所获得的 W/Cu 接头的最大拉伸强度和弯曲强度分别为 ~ 172 MPa 和 ~ 232 MPa，与纯铜相比达到了非常高的水平。相应的裂缝具有延展性。W/Cu 接头的微观测试表明 W 和 Cu 之间发生扩散，W/Cu 扩散层的厚度约为 22 nm。通过扩散，成功构建了冶金结合界面，这是W/Cu接头强度高的根本原因。当结合温度接近 TmCu 时，W 和 Cu 之间的扩散可能是由 Cu 的高温结构引起的，这需要进一步研究。