Abstract 17-4 PH stainless steel and Al2O3 ceramic were successfully vacuum brazed using graphene reinforced Ag-Cu-Ti brazing alloy. In this paper, the effects of operating parameter such as brazing temperature, holding time and graphene amount on the microstructure and mechanical properties of the brazed joints were systematically studied. The experiment revealed that with the elevation of brazing temperature and holding time, the shear strength of 17-4 PH stainless steel and Al2O3 ceramic joints brazed with Ag-Cu-Ti filler alloy increased first, getting the maximum 170 MPa at 880 °C for 10 min and then declined. When the joint brazed with 0.1 wt % graphene reinforced Ag-Cu-Ti composite filler, the maximum shear strength reached 212 MPa that was 25% higher than the joint with single Ag-Cu-Ti filler metal. Moreover, fracture path of the 17-4 PH stainless steel and Al2O3 ceramic joint with 0.1 wt % graphene reinforced Ag-Cu-Ti was changed from the ceramic to the reaction layer that was closed to Al2O3 substrate. The improvement of the joint shear strength was chiefly benefited from the formation of TiC particle that reinforced brazing seam and the refinement of joint microstructure.

中文翻译：

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石墨烯增强Ag-Cu-Ti钎焊合金钎焊17-4PH不锈钢与Al2O3陶瓷接头的显微组织和力学性能

摘要 采用石墨烯增强Ag-Cu-Ti 钎焊合金成功真空钎焊17-4 PH 不锈钢和Al2O3 陶瓷。本文系统地研究了钎焊温度、保温时间和石墨烯用量等操作参数对钎焊接头显微组织和力学性能的影响。实验表明，随着钎焊温度和保温时间的升高，Ag-Cu-Ti钎料钎焊的17-4PH不锈钢和Al2O3陶瓷接头的剪切强度首先增加，在880℃时达到最大170MPa 10 分钟，然后拒绝。当接头采用 0.1 wt% 石墨烯增强 Ag-Cu-Ti 复合填料钎焊时，最大剪切强度达到 212 MPa，比采用单一 Ag-Cu-Ti 填料金属的接头高 25%。而且，17-4 PH 不锈钢和含有 0.1 wt% 石墨烯增强 Ag-Cu-Ti 的 Al2O3 陶瓷接头的断裂路径从陶瓷转变为靠近 Al2O3 基底的反应层。接头剪切强度的提高主要得益于增强焊缝的TiC颗粒的形成和接头微观结构的细化。