(西安交通大學(xué) 金屬材料強(qiáng)度國家重點實驗室，西安 710049)
摘 要: 采用純鋁/硬鋁(Al/LY12)爆炸復(fù)合板通過電子束焊接制得界面裂紋四點彎曲試樣。由于強(qiáng)度錯配， Al/LY12界面裂紋頂端局部的變形是銳化與鈍化的復(fù)合型，但在疲勞載荷下其整體裂端應(yīng)力應(yīng)變場仍然可由純I型應(yīng)力強(qiáng)度因子主導(dǎo)，可以采用和單材料試樣相同的方式進(jìn)行界面裂紋的疲勞擴(kuò)展行為研究。界面裂紋可在較低的外載水平下啟始擴(kuò)展，但爆炸焊接界面存在的波紋使得界面裂紋的擴(kuò)展速率出現(xiàn)波動，并且阻礙裂紋的擴(kuò)展，相同外載下Al/LY12界面裂紋的疲勞擴(kuò)展速率低于單材料LY12的疲勞擴(kuò)展速率。
關(guān)鍵字: 金屬層合板； 界面裂紋； 疲勞擴(kuò)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
