(西安交通大学 金属材料强度国家重点实验室，西安 710049)
摘 要: 采用纯铝/硬铝(Al/LY12)爆炸复合板通过电子束焊接制得界面裂纹四点弯曲试样。由于强度错配， Al/LY12界面裂纹顶端局部的变形是锐化与钝化的复合型，但在疲劳载荷下其整体裂端应力应变场仍然可由纯I型应力强度因子主导，可以采用和单材料试样相同的方式进行界面裂纹的疲劳扩展行为研究。界面裂纹可在较低的外载水平下启始扩展，但爆炸焊接界面存在的波纹使得界面裂纹的扩展速率出现波动，并且阻碍裂纹的扩展，相同外载下Al/LY12界面裂纹的疲劳扩展速率低于单材料LY12的疲劳扩展速率。
关键字: 金属层合板； 界面裂纹； 疲劳扩展
explosive bonded Al/LY12 interface
（State Key Laboratory for Mechanical Behavior of Materials,
Xi′an Jiaotong University, Xi′an 710049, P.R.China）
Abstract:Bimetallic specimens were produced from explosion clad Al/LY12 and electron beam welding of bulk Al and bulk LY12 to the respective surface. Cracks were introduced at the interface in the specimens by milling and spark-erosion. Finite element computation was undertaken to evaluate the J-integral of the interfacial crack of specimens.It is indicated that the standard ASTM-E83 for single material can also be applied to the measurement of fatigue crack propagation along the interface of the bimaterial specimens. The interfacial fatigue crack growth behaviors were investigated under four points bending condition. The results show that the crack growth velocity at the interface is some slower than that of bulk LY12 under the same loading condition, although the interfacial crack starts togrow at low load level comparing to that of bulk alloy. The wavy interface caused the undulation in the rate of interfacial fatigue crack growth and particularly retarded the crack growth velocity of interface cracks.
Key words: explosive clad metals； interfacial crack； fatigue growth
