DZ38G高温合金扩散钎焊微观结构分析

Study on Microstructure of DZ38G High-temperature Alloy Diffusion Brazing Joint

在真空环境下采用Ni-Si-B中间层,扩散钎焊DZ38G高温合金,扩散连接温度为1050℃,扩散连接时间为30～70 min,焊后均质化保温温度为1050℃,保温时间为300 min。研究了接头的微观结构。研究表明:等温凝固完成前,接头主要有四种不同的相构成:初始共晶的γ固溶体、Ni基硼化物、共晶的γ固溶体和母材金属;在1050℃下,扩散钎焊时间70 min以上,可完成等温凝固。

Using Ni-Si-B intermediate layer in vacuum environment, DZ38G high-temperature alloy was diffusion-brazed on 1050℃ welding temperature for 30-70 min and 1050 ℃ homogenization temperature for 300 min. Microstructure of joints was researched. The result showed that before the isothermal solidification completed, joint had four phases.The four phases were proeutectic γ-solid solution, Nickel-rich boride phase, eutectic 7-solid solution and base metal. At 1050 ℃, welding time over 70 min, the isothermal solidification was completed.