Cu/W-Ni-Co/Ni多中间层的钨/钢扩散连接

采用铜箔/90W-5Ni-5Co(质量分数,%)混合粉末/镍箔复合中间层,在加压5 MPa、连接温度1120℃、保温60 min的工艺条件下,对纯钨(W)和0Cr13Al钢进行了连接。利用SEM、EDS、电子万能试验机及水淬热震实验等手段研究了接头的微观组织、成分分布、断口特征、力学性能及抗热震性能。结果表明,连接接头由钨母材、Cu-Ni-Co合金层、钨基高密度合金层、镍层、钢母材5部分组成。接头中的钨基高密度合金层由90W-5Ni-5Co混合粉末固相烧结生成,其Ni-Co粘结相和钨颗粒相冶金结合且分布均匀。钨基高密度合金层与钨母材以瞬间液相扩散连接机制实现了良好结合。接头剪切强度达到286 MPa,断裂均发生在钨基高密度合金层/镍层结合区域,断口形貌呈现为韧性断裂。经过60次700℃至室温的水淬热震测试,接头无裂纹出现。

Diffusion Bonding between Tungsten and Steel with Cu/W-Ni-Co/Ni Multi-Interlayer

Bonding between tungsten and 0Cr13Al steel using a Cu/90W-5Ni-5Co powder mixtures/Ni multi-interlayer, was carried out in vacuum for 60 min at 1120 oC with a pressure of 5 MPa. The microstructures, composition distribution and fracture characteristics of the joints were studied by SEM and EDS. Joint properties were tested by shear experiments and thermal shock test. The results show that the joints comprise of tungsten/Cu-Ni-Co/tungsten heavy alloy/Ni/steel. Among them, the tungsten heavy alloy sub-layer, which is composed of uniformly distributed tungsten phase and Ni-Co matrix, is formed by solid phase sintering of 90W-5Ni-5Co powder mixtures. Sound bonding between tungsten and tungsten heavy alloy sub-layer are realized based on the transient liquid phase bonding mechanism. The average shear strength of 286 MPa has been obtained, and all the joints fracture at bonding zone of tungsten heavy alloy sub-layer and Ni sub-layer during shear testing. The results of the thermal shock tests indicate that all joints could withstand 60 cycles from 700 oC to room temperature in water.