The effects of postweld heat treatment on the microstructure and metallurgical properties of a bronze-carbon steel (st37) explosively bonded interface were studied. Explosive welding was done under 1.5- and 2-mm standoff distances and different conditions of explosive charge. Samples were postweld heat treated for 4 and 16 h in the furnace at 250 ℃ and 500 ℃ and then air cooled. Laboratory studies using optical microscopy, scanning electron microscopy, and microhardness testing were used to evaluate the welded samples. Microstructural examinations showed that by increasing the standoff distance and the explosive charge, the interface of bronze to steel became wavier. The microhardness test result showed that the hardness of the samples was higher near the joint interface compared with other areas because of the intensive plastic deformation, which was caused by the explosion force. The results show that increasing the heat treatment temperature and time caused the intermetallic compounds' layer thickness to increase, and, because of the higher diffusion of copper and tin, the iron amount in the intermetallic compounds decreased. Also, because of the increase in heat treatment temperature and time, internal stresses were released, and the interface hardness decreased.%研究了焊后热处理对青铜-碳钢爆炸结合界面组织和冶金性能的影响.在不同装药条件下,分别在1.5 mm和2 mm距离下进行了爆炸焊接.在250℃和500℃的炉中进行4和16 h的焊后热处理,再进行风冷处理.采用光学显微镜、扫描电子显微镜和显微硬度测试对焊接试样进行了实验研究.显微组织测试表明,随着距离的增加和装药量的增加,青铜与钢的界面逐渐变薄.显微硬度测试结果表明,由于爆炸力引起的强烈塑性变形,接头界面附近的硬度较高.结果表明,随着热处理温度的升高和热处理时间的延长,金属间化合物的层厚增加,金属间化合物中的铁含量降低,铜和锡的扩散越快,金属间化合物中的铁含量越低.同时,由于热处理温度的升高和热处理时间的延长,内部应力释放,界面硬度降低.
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