选择3.5%NaCl溶液浸泡腐蚀试验方法,采用扫描电镜观察分析腐蚀形貌和Image Pro Plus软件定量统计腐蚀面积率,研究了Fe对ER5356焊丝熔敷金属耐腐蚀性能的影响。结果表明,熔敷金属腐蚀微观形貌呈点蚀特征,点蚀坑在第二相周围萌生,点蚀机...选择3.5%NaCl溶液浸泡腐蚀试验方法,采用扫描电镜观察分析腐蚀形貌和Image Pro Plus软件定量统计腐蚀面积率,研究了Fe对ER5356焊丝熔敷金属耐腐蚀性能的影响。结果表明,熔敷金属腐蚀微观形貌呈点蚀特征,点蚀坑在第二相周围萌生,点蚀机理为阳极溶解;随着焊丝中Fe元素含量的增加,熔敷金属点蚀坑面积率呈线性增加。展开更多
Transient creep at very low strain rates （less than 10-10 s-1） is still unclear. The traditional uniaxial creep testing is less useful due to unsatisfied resolution strain （~10-6）. To study transient creep behavio...Transient creep at very low strain rates （less than 10-10 s-1） is still unclear. The traditional uniaxial creep testing is less useful due to unsatisfied resolution strain （~10-6）. To study transient creep behavior at such low strain rates, a high-resolution strain measurement using the helicoid spring specimen technique was employed in a fine-grained Al-5356 alloy at temperatures ranging from 0.47Tm to 0.74Tm （Tm： melting point）. To clarify transient creep mechanism at such low strain rates, transmission electron microscopy （TEM） was used in microstructure observation of crept specimens. The abnormal transient creep, high temperature strengthening at T〉Tp （Tp： the phase transformation temperature, 0.58Tm） or intermediate temperature softening at 0.4Tm〈T￡Tp and double-normal type （creep curves including double work-hardening stages） at T=Tp, were firstly observed. The substructure observation in a crept specimen at T=0.58Tm and e=1×10-4 shows pile-up dislocations including many small jogs with equal interval, and dislocations emitted from grain boundaries. The b-Al3Mg2 phase dissolves under the condition of testing temperatures higher than 523 K, which causes solid-solution quantity of Mg atoms to increase. Therefore, the “abnormal transient creep” may be related to the difference of solid solution strengthening caused by phase change during the creep tests.展开更多
文摘选择3.5%NaCl溶液浸泡腐蚀试验方法,采用扫描电镜观察分析腐蚀形貌和Image Pro Plus软件定量统计腐蚀面积率,研究了Fe对ER5356焊丝熔敷金属耐腐蚀性能的影响。结果表明,熔敷金属腐蚀微观形貌呈点蚀特征,点蚀坑在第二相周围萌生,点蚀机理为阳极溶解;随着焊丝中Fe元素含量的增加,熔敷金属点蚀坑面积率呈线性增加。
基金Project(12JCYBJC32100)supported by Tianjin Research Program of Application Foundation and Advanced Technologyin part by Grants-in-Aid from the Japan Society for the Promotion of Science(JSPS)
文摘Transient creep at very low strain rates （less than 10-10 s-1） is still unclear. The traditional uniaxial creep testing is less useful due to unsatisfied resolution strain （~10-6）. To study transient creep behavior at such low strain rates, a high-resolution strain measurement using the helicoid spring specimen technique was employed in a fine-grained Al-5356 alloy at temperatures ranging from 0.47Tm to 0.74Tm （Tm： melting point）. To clarify transient creep mechanism at such low strain rates, transmission electron microscopy （TEM） was used in microstructure observation of crept specimens. The abnormal transient creep, high temperature strengthening at T〉Tp （Tp： the phase transformation temperature, 0.58Tm） or intermediate temperature softening at 0.4Tm〈T￡Tp and double-normal type （creep curves including double work-hardening stages） at T=Tp, were firstly observed. The substructure observation in a crept specimen at T=0.58Tm and e=1×10-4 shows pile-up dislocations including many small jogs with equal interval, and dislocations emitted from grain boundaries. The b-Al3Mg2 phase dissolves under the condition of testing temperatures higher than 523 K, which causes solid-solution quantity of Mg atoms to increase. Therefore, the “abnormal transient creep” may be related to the difference of solid solution strengthening caused by phase change during the creep tests.
