摘要
按照HB5142-1996实验标准,采用紧凑拉伸(CT)试样测定铸造铝合金A356的平面断裂韧度KIC值,并使用光学显微镜(OP)、扫描电镜(SEM)以及能谱分析仪(ESA)等现代技术观察了合金的组织、断口形貌并对其夹杂物成分进行了鉴定,从微观角度给予解释。试验结果表明:铝合金A356铸件的KIC值15～20 MPa.m1/2,接近2×××系(Al-Cu合金)和7×××系(Al-Zn-Mg-Cu合金)变形铝合金的下限,断口为准解理断裂,铸造缺陷明显降低KIC值。最后提出了一些提高平面断裂韧性的改进措施。
The fracture toughness KIC for A356 casting aluminum alloy was obtained by measured compact tension specimen according to the test criteria HB5142-1996. Microstructure, fractograph were observed and inclusion component was analyzed by OM （optical microscope）, SEM （Scanning Electron Microscope）, ESA （energy spectrum analysis ）. The micro-mechanism of the fracture was explained. The results show that the value of KIC is 15-20 MPa· m^1/2, approximate to the low limit of some wrought aluminum alloy, it is quasi-cleavage fracture and some casting defects affect the value of KIC, such as gas cavity, inclusion, dendritic segregation. Some methods are given to improve the fracture toughness KIC.
出处
《铸造》
EI
CAS
CSCD
北大核心
2007年第5期520-522,共3页
Foundry
