Abstract In this study, the effect of post-weld heat-treatment (PWHT) on the interface microstructure and its mechanical properties in the three-layered explosive welded (EXWed) SS321/AA1050/AA5083 joints fabricated with different stand-off distances were investigated. The welded specimens were heat-treated at 250 and 350 °C for 1000–10000 s. The microscopy studies exhibited that the AA5083/AA1050 interface was smooth and continuous in all conditions and was free of cracks since the SS321/AA1050 interface contained a reaction layer with variable thickness, having discontinuous and wavy morphology including some transverse and longitudinal cracks. As the stand-off distance increased, the SS321/AA1050 interface appearance altered from smooth to be wavier, and the average thickness of the developed reaction layer was enhanced from 4.95 to 6.7 μm. By PWHT, the thickness of the interfacial layer increased in proportion to the diffusion kinetics and reached a maximum of 18.56, and 15.02 μm for samples joined with a stand-off distance of 6.75 and 6 mm, respectively. For specimens with a stand-off of 6.75 and 6 mm, the diffusion driving energy values were 46.6 and 42.4 kJ mol−1, respectively, while the constant diffusion values were calculated to be 142.2 and 45.3 m2 s−1, respectively. For the samples with an applied distance of 6.75 mm, by increasing the treatment temperature and retention time, the average concentration of aluminum in the reaction layer increased since the concentration of iron decreased. Moreover, the compressive-shear strength was declined from 94.6 to 56.7 MPa. For the sample with a longer stand-off distance, lower shear strength reduction was examined after thermal treatment due to higher collision energy, the formation of wavy interface with larger amplitude, and greater plastic deformation, as well as, stronger mechanical interlocking.

中文翻译：

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三层 SS321/AA1050/AA5083 爆炸焊缝：焊后热处理对界面演变及其机械强度的影响

摘要 本研究研究了焊后热处理（PWHT）对不同间距焊接的三层爆炸焊接（EXWed）SS321/AA1050/AA5083接头界面组织及其力学性能的影响。 . 焊接试样在 250 和 350°C 下热处理 1000-10000 秒。显微镜研究表明，AA5083/AA1050 界面在所有条件下都是光滑和连续的，并且没有裂纹，因为 SS321/AA1050 界面包含一个厚度可变的反应层，具有不连续和波浪形形态，包括一些横向和纵向裂纹。随着间隔距离的增加，SS321/AA1050界面外观由光滑变为波浪状，反应层的平均厚度从4.95增加到6.7μm。通过 PWHT，界面层的厚度与扩散动力学成比例增加，对于以 6.75 和 6 毫米的间距连接的样品，界面层的厚度分别达到 18.56 和 15.02 微米。对于间距为 6.75 和 6 mm 的试样，扩散驱动能值分别为 46.6 和 42.4 kJ mol-1，而计算出的恒定扩散值分别为 142.2 和 45.3 m2 s-1。对于施加距离为6.75 mm的样品，随着处理温度和停留时间的增加，反应层中铝的平均浓度随着铁浓度的降低而增加。此外，压缩剪切强度从 94.6 MPa 下降到 56.7 MPa。对于距离较长的样品，