Abstract Elastic modulus and hardness of Inconel 625/BNi-2 vacuum brazed joint microregion are investigated by the high temperature nanoindentation technique, and its microstructure is also inspected. The results show that the joint includes three parts of brazing seam, diffusion zone and metal substrate. Needle-like, granular-like and grain boundary shape precipitates distribute in the diffusion zone. The needle-like white precipitates are consisted of Cr–Mo rich borides, black granular-like precipitates are Cr-rich borides and the grain boundary shape precipitates are Mo-rich borides. Elastic modulus of the diffusion zone is larger than those of brazing seam and metal substrate under the same temperature. The tested elastic modulus decreases with increasing of the maximum press depth, while it increases with increasing of the applied loading rate. When the maximum press depth is larger than 800 nm or the applied loading rate higher than 10 mN/s, the elastic modulus of different regions keeps almost the same. For the hardness of the brazed joint micro-region, the value at high temperature is higher than those of at room temperature due to the existing of Ni3Al. The elastic modulus of brazed joint micro-region present linear relationship with the temperature and hardness.

中文翻译：

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高温纳米压痕对Inconel 625/BNi-2真空钎焊接头微区弹性模量和硬度表征

摘要 采用高温纳米压痕技术研究了Inconel 625/BNi-2真空钎焊接头微区的弹性模量和硬度，并对其微观结构进行了检测。结果表明，接头包括钎焊缝、扩散区和金属基体三部分。针状、粒状和晶界状沉淀物分布在扩散区。白色针状析出物为富Cr-Mo硼化物，黑色粒状析出物为富Cr硼化物，晶界状析出物为富Mo硼化物。在相同温度下，扩散区的弹性模量大于焊缝和金属基体的弹性模量。测试的弹性模量随着最大压入深度的增加而降低，而随着施加载荷率的增加而增加。当最大压入深度大于 800 nm 或施加的加载速率大于 10 mN/s 时，不同区域的弹性模量几乎保持不变。由于Ni3Al的存在，钎焊接头微区的硬度在高温下高于室温。钎焊接头微区的弹性模量与温度和硬度呈线性关系。