摘要
测试不同热处理条件下GH864合金在650℃空气中疲劳/蠕变交互作用下的裂纹扩展速率,分析热处理制度及组织特征对合金裂纹扩展速率的影响。通过组织分析试验、裂纹扩展速率试验和断口形貌分析,对比不同组织状态下GH864合金的微观组织及裂纹扩展行为,并用Paris公式对裂纹扩展速率的结果进行描述。结果表明:热处理后合金的裂纹扩展速率都明显降低;晶粒度对合金的裂纹扩展速率影响较大,且粗晶组织能显著降低裂纹扩展速率;晶界析出相对裂纹扩展速率有较大作用,而强化相γ?相大小对裂纹扩展速率影响不明显。从组织形貌及断口分析可较好解释不同热处理制度裂纹扩展速率曲线的试验结果。具有疲劳条纹特征断口对应较慢的裂纹扩展速率,而沿晶断裂对应较快的裂纹扩展速率。
Crack propagation rates after different heat treatments for GH864 alloy are measured under fatigue/creep interaction condition at 650℃ in air. The influence of heat treatment and microstructure are analyzed. The microstructure and crack propagation behavior of GH864 alloy are studied by means of microstructure analysis, fatigue crack growth and fracture morphology analysis. The crack propagation rates have a good description by Paris formula. The results indicate that the fatigue crack growth rates of alloys are decreased after these heat treatments; the grain sizes affect strongly on crack propagation rates and the coarse grain structure obviously reduces the fatigue crack growth; the precipitations of grain boundary is important to the crack propagation rate of GH864 alloy, but the size ofγ prime phase strengthen particles has little effect on the fatigue crack growth. The microstructure morphology and fracture analysis can well explain the test results of crack propagation curves after different heat treatments. The fracture with fatigue striation character corresponds to the lower crack growth rates, while the intergranular fracture corresponds to higher rates.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2009年第5期79-84,共6页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(50771011)