7BO4铝合金断裂过程的研究

用材料介观力学(介于宏观和微观之间)手段研究了7B04高强高韧铝合金在拉伸试验过程中的塑性变形的产生、旋转和材料的断裂过程。试验结果表明:7B04合金中有害杂质相是有棱角的颗粒,以几个颗粒团簇在一起,或是单独分散在基体材料中。在拉伸过程中,对材料塑性变形的产生、发展的观察发现,杂质相附近是材料的薄弱环节。随着塑性变形的发展,在这个区域流变曲线产生大角度的旋转,表明杂质相阻碍了变形的流畅进行,同时还发现微裂纹首先在杂质相的边界中产生。杂质相的消除或减少是提高7B04合金材料强塑性的主要途径之一。

Study on Fracture Process of 7B04 Aluminum Alloy

By using materials Mesomechanics means (it is be- tween Micro and Macro),the distribution of rotation field and fracture behavior of 71304 aluminum alloy with high strength and high ductility in the plastic deformation are investigated.There are some harmful foreign phases in the 7B04 Alloy.Its topo- graphical pattern appears as a cluster gathered from many grains with cornered boundary,otherwise scatters discretely in the ma- trix materials.Being gathered together the impurity phase grains with cornered boundary connect loosely,therefore,the potential source to micro-cracking is presented.In the process of material deformation turned to fracture we discovered that the neighbor- hood of impurity phase is the region with intensive change of ro- tation field,the microscopic crack is generated in the impurity phase firstly,and with increasing of the load the stress divergence occurs in the point of crack,and then the fracture occurs in that place.The impurity phase is the weak link that leads the materi- als to be fractured.The results indicate that elimination or feasi- ble way to improve strength and ductility of 7B04 alloy materi- als.