热轧变形对快凝Al－Fe－V－Si粉热挤合金断裂行为的影响

研究了不同热变形条件下用快餐Ａｌ—Ｆｅ—Ｖ—Ｓｉ合金粉挤压成形样品的拉伸断裂行为．结果表明，在沿轧制方向拉伸的试样中，与板面平行的颗粒界面（ＬＴ界面）处形成的微裂纹不影响主裂纹的扩展，沿与板材纵截面平行的颗粒界面（ＬＳ界面）的开裂可能导致试样反常断裂，沿与板材横截面平行的颗粒界面（ＴＳ界面）则易成为主裂纹的低能扩展路径，使试样沿颗粒断裂．热轧变形使粉末ＬＳ，ＴＳ界面的强度提高快于ＬＴ界面，导致热轧变形至一定程度（３０％变形量）时试样的断裂方式改变．断裂强度与延伸率的不同变化规律与断裂方式的改变及其后的形变硬化有关．

INFLUENCE OF HOT ROLLING ON FRACTURE BEHAVIOUR OF Al-Fe-V-Si ALLOY PREPARED BY HOT EXTRUSION OF RAPIDLY SOLIDIFIED POWDERS

The room temperature fracture behaviours of the alloy prepared by rapidly solidified Al-8.5Fe-1.3V-1.7Si powders under different deforming conditions have been investigated. The results revealed that the propagation mode of main crack related to the orientation of powder boundaries when the specimen fractured. For the specimen tensed along extrusion direction, the microcracks along rolling plane did not affect propagation of the main cracks; the microcracks along vertical section might lead to unusual fracture; the cross-section boundaries are ready to become the low energy propagation path for main crack. Hot rolling improved cohesion strength for boundaries along the vertical section and cross-section more than ones along rolling plane, resulting in the change of fracture mode at a certain deformation (30%). The different variation regularities for fracture strength and elongation relate to the fracture mode and follow-on deformation hardening.