【摘要】 结合多年断裂韧性测试试验的经验,研究了较薄板材C(T)试验件测定KR曲线和断裂韧性的注意事项。通过试验测定了LY12CZ铝合金及其搅拌摩擦焊接接头的KR曲线和断裂韧性,并通过金相显微镜对焊接接头的显微组织进行了观察。试验结果表明,由于焊缝中心处的致密再结晶微观组织,搅拌摩擦焊接接头的断裂韧性明显高于母材,且裂纹垂直于板材轧制方向的母材和焊接接头试验件,断裂韧性均高于裂纹平行于板材轧制方向的试验件。此外,试验结果表明C(T)试验件的断裂韧性值与面内尺寸有关,尺寸越大,断裂韧性值越高。更多还原

【Abstract】 Based on years’ experience in fracture toughness tests,the matters need attention for KRcurve and fracture toughness determination using thin compact tension( C( T)) specimen were studied.The KRcurve and fracture toughness of LY12 CZ alloy and friction stir welded joints were determined according to proposed test method.The microstructures of FSW joint were also observed utilizing metalloscope.The test result demonstrates that the fracture toughness of friction stir welded LY12 CZ alloy is higher than that of the parent alloy,because the weld nugget presents fine recrystallized structure.It is also found that the fracture toughnesses with crack perpendicular to rolling direction are higher than those with crack parallel to rolling direction for both welded and parent alloy.In addition,the test result indicates that the fracture toughness of C( T) specimen is related to inplane dimension,and that the fracture toughness increases with the increase of in-plane dimension.更多还原