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在工程上得到日益广泛应用的爆炸焊,只依靠光学金相很难了解结合层的细节,本工作用电子金相研究了18/8奥氏体不锈钢和26/1铁素体不锈钢爆炸焊结合层。为了克服不一定在结合层处穿孔的困难,采用了双喷和窗法结合的办法来制备电镜试样。图1是结合区的光学金相照片。结合界面呈波浪形,两侧有明显的塑性变形,波浪形界面上有间断的块状熔化区,其成份相当于两者以1:1混合的结果。图2、3是非块状熔化区处结合层的电子金相照片。由SAD确定γ/α的界面如照片中箭头所示。图2中的结合层处发生了再结晶。图3中的除再结晶外还有熔化现象,由于爆炸焊高压的瞬时作用,焊接件两者高速相撞,产生表面喷射和强烈变形,使界面处温度升高,原子发生微小距离扩散甚至熔化而形成冶金结合。同时,变形金属发生了再结晶,在微秒级时间内发生的再结晶与通常情况下的有明显不同。除了晶粒极细小外,晶内还保留了较高的位错密度。在结合层两侧和奥氏体和铁素体中位错密度极高,奥氏体中除了有大量孪晶外,在离结合层界面～40μm以外处有α′马氏体,在近结合层处的α′可能因温度升高而反转成γ。
Explosion welding, which is widely used in engineering, is hard to understand the details of the bonding layer only by optical metallography. This work studied the combination of 18/8 austenitic stainless steel and 26/1 ferritic stainless steel explosive welding Floor. In order to overcome the difficulty of perforation not necessarily in the bonding layer, a dual spray and window method was used to prepare the electron microscope sample. Figure 1 is an optical metallographic photograph of the binding zone. The interface is wavy, with obvious plastic deformation on both sides. There are intermittent melting zones on the wavy interface. Its composition is equivalent to a 1: 1 mixture of the two. Figures 2 and 3 are electron metallographs of the bond layer at the non-lump melting zone. The γ / α interface determined by SAD is shown by the arrows in the photo. Recrystallization occurred at the bonding layer in FIG. 2. In addition to the recrystallization in Figure 3, there are melting phenomena. Due to the instantaneous action of the high pressure of the explosive welding, the welding parts collide at high speed, resulting in surface spraying and strong deformation, causing the temperature at the interface to increase, and the atoms to diffuse and even melt at a small distance The formation of metallurgical bonding. At the same time, the deformed metal recrystallizes and the recrystallization that takes place in the microsecond time period is markedly different from the usual case. In addition to very fine grains, the crystal also retains a higher dislocation density. Dislocation density is extremely high in both austenite and ferrite in the bonding layer. In addition to a large number of twins in the austenite, α ’martensite is present at ~ 40 μm away from the interface of the bonding layer, The α ’at the layer may be reversed to γ due to the temperature increase.