The TLPB behavior of Ni/Ni-Si-B and Ni-Cr-Fe/Ni-Si-B base metal/braze joints was examined to determine the role chromium in the base metal has during joining of Ni-based alloys using a boron-bearing braze metal. The isothermal solidification (IS) rate in these two braze joints at 1075 °C was measured using DSC. Microstructural evolution within the diffusionally affected zone (DAZ) was examined both in terms of the type of borides formed and their volume fraction, using image analysis and phase equilibria predictions. Overall, the results show that when the base metal (BM) contains an appreciable concentration of Cr the IS rate decreases significantly. This was due to the formation of a low volume fraction of CrB within the DAZ, dictated by phase equilibria. Conversely, in the pure Ni base metal (BM) the thermodynamically favored boride was Ni₃B, present at high volume fractions, resulting in rapid IS. A direct link between the boride microstructure of the DAZ and the rate of IS was established.

检查了Ni / Ni-Si-B和Ni-Cr-Fe / Ni-Si-B贱金属/钎焊接头的TLPB行为，以确定在使用硼连接Ni基合金期间贱金属中铬的作用轴承铜焊金属。使用DSC测量这两个钎焊接头在1075°C下的等温凝固（IS）速率。使用图像分析和相平衡预测，根据形成的硼化物类型及其体积分数，检查了扩散影响区（DAZ）内的微结构演变。总体而言，结果表明，当贱金属（BM）包含一定浓度的Cr时，IS率显着降低。这是由于在DAZ中形成了低体积的CrB，这是由相平衡决定的。相反，在纯Ni基金属（BM）中，热力学上受欢迎的硼化物是Ni₃ B，以高体积分数存在，导致快速IS。在DAZ的硼化物微结构与IS率之间建立了直接联系。