扩散连接制备20钢预制人工缺陷试块的形变及界面表征研究

Deformation and Interface Characterization of 20 Steel Prefabricated Artificial Defect Test Block Prepared by Diffusion Bonding

在不同最大轴向变形条件下,采用扩散连接制备了内部含有U形、V形和矩形预制人工缺陷的圆柱金属试块,利用激光三维扫描、超声波C扫描、体视显微镜和金相显微镜对试块及预制缺陷的形变、界面熔合及其超声波反馈进行了分析。结果表明:圆柱试块的高度、径向形变量均随着最大轴向变形的减小而减小。试块高度实际形变量略大于最大轴向变形量,试块径向变形量呈中间高、两端低的近似“鼓”状变形。U形、V形和矩形三类预制缺陷的高度形变量与最大轴向变形的线性相关性强度依次为矩形>U形>V形。缺陷宽度形变受扩散界面与缺陷轮廓边界夹角影响,V形缺陷稳定性差、形变大。不同最大轴向变形下的界面熔合状态良好,超声波C扫描结果显示预制缺陷明显且轮廓清晰,无扩散连接不佳所致的缺陷信息。

Under different maximum axial deformation conditions, the cylindrical metal test blocks containing U-shaped,V-shaped and rectangular prefabricated artificial defects were prepared by diffusion bonding method. The deformation of the block and prefabricated defects, interfacial fusion and the ultrasonic feedback were analyzed by laser 3D scanning, ultrasonic C-scanning, stereo light microscope and metallographic microscopy. The results show that the height and radial deformations of the cylindrical test block decrease with the decrease of the maximum axial deformation. The actual height deformation of the test block is slightly bigger than the maximum axial deformation, and the test block radial deformation shows an approximate "drum" shape with the middle high and the two ends low. The linear correlation level between the height deformation of U-shaped, V-shaped, rectangular prefabricated defects and the maximum axial deformation is rectangle>U-shaped>V-shaped. The deformation of the defect width is affected by the angle between the diffusion interface and the defect contour boundary, and the V-shaped defect has poor stability and large deformation.The interfacial fusion state under different maximum axial deformations is good, and the ultrasonic C-scanning results show that the prefabricated defects are obvious and the outline is clear, and there is no defect information due to poor diffusion bonding.