The stress corrosion cracking(SCC) behavior and mechanism of 7050-T7451 aluminum alloy under wet-dry cyclic conditions were investigated. Slow strain rate tests(SSRTs) and electrochemical tests were used to study the ...The stress corrosion cracking(SCC) behavior and mechanism of 7050-T7451 aluminum alloy under wet-dry cyclic conditions were investigated. Slow strain rate tests(SSRTs) and electrochemical tests were used to study the effects of dry/wet ratio(DWR) and pre-immersion on SCC.Fracture and side surface characterizations were observed by scanning electron microscopy(SEM).The results demonstrate that SCC susceptibility decreases with an increase of the DWR. With an increase of the pre-immersion time, both continuous pre-immersion(CP) and wet-dry cyclic preimmersion(WDP) samples are more sensitive to SCC, and the cracking mode in the SCC fracture region is intergranular. Furthermore, the effect of WDP on SCC is greater than that of CP when the total time immersed in solution before an SSRT is the same with each other. In fact, each single wetdry cycle can be divided into three processes with respect to the change of solution on samples’ surface. Volatilization of water on the surface results in an increase in solute concentration, thus accelerating corrosion.展开更多
In this study,the corrosion behaviors of an as-extruded Mg–4%Zn–2%Y–1.8%Nd(in wt.%)alloy in different physiological saline solutions were investigated and compared.The results indicated that the alloy in the 9 g/L ...In this study,the corrosion behaviors of an as-extruded Mg–4%Zn–2%Y–1.8%Nd(in wt.%)alloy in different physiological saline solutions were investigated and compared.The results indicated that the alloy in the 9 g/L NaCl had the higher corrosion resistance than that containing with CaCl_(2) and NaHCO3.Moreover,it demonstrated that the corrosion behaviors of the alloy in two types of solutions were all dependent on the pre-immersion time.In the 9 g/L NaCl solution,the corrosion current densities of the alloy decreased firstly with the pre-immersion time being<4 h and then increased with the pre-immersion time prolonging from 4 to 48 h.However,in the 9 g/L NaCl solution containing with CaCl_(2) and NaHCO3,the corrosion current density of the alloy exhibited the adverse trend with the prolonging the pre-immersion time.Failure analysis demonstrated that the changes of corrosion resistance in two solutions were mainly dominated by the constituents formed in surface films.展开更多
基金co-supported by the National Natural Science Foundation of China (No. 51671013)the Beijing Nova Program of China (No. Z161100004916061)
文摘The stress corrosion cracking(SCC) behavior and mechanism of 7050-T7451 aluminum alloy under wet-dry cyclic conditions were investigated. Slow strain rate tests(SSRTs) and electrochemical tests were used to study the effects of dry/wet ratio(DWR) and pre-immersion on SCC.Fracture and side surface characterizations were observed by scanning electron microscopy(SEM).The results demonstrate that SCC susceptibility decreases with an increase of the DWR. With an increase of the pre-immersion time, both continuous pre-immersion(CP) and wet-dry cyclic preimmersion(WDP) samples are more sensitive to SCC, and the cracking mode in the SCC fracture region is intergranular. Furthermore, the effect of WDP on SCC is greater than that of CP when the total time immersed in solution before an SSRT is the same with each other. In fact, each single wetdry cycle can be divided into three processes with respect to the change of solution on samples’ surface. Volatilization of water on the surface results in an increase in solute concentration, thus accelerating corrosion.
基金supported by the National Key Research and Development Program of China under Grant(Nos.2017YFB0702001 and 2016YFB0301105)the Liaoning Province’s project of“Revitalizing Liaoning Talents”(XLYC1907062)+7 种基金the National Natural Science Foundation of China Projects under Grant(Nos.51871211 and 51701129)the Doctor Startup Fund of Natural Science Foundation Program of Liaoning Province(No.2019-BS200)the Strategic New Industry Development Special Foundation of Shenzhen(JCYJ20170306141749970)the funds of the International Joint Laboratory for Light Alloysthe Liaoning BaiQianWan Talents Programthe Domain Foundation of Equipment Advance Research of 13th Five-year Plan(61409220118)the Innovation Fund of Institute of Metal Research(IMR),Chinese Academy of Sciences(CAS)the National Basic Research Program of China(973 Program)project under Grant No.2013CB632205。
文摘In this study,the corrosion behaviors of an as-extruded Mg–4%Zn–2%Y–1.8%Nd(in wt.%)alloy in different physiological saline solutions were investigated and compared.The results indicated that the alloy in the 9 g/L NaCl had the higher corrosion resistance than that containing with CaCl_(2) and NaHCO3.Moreover,it demonstrated that the corrosion behaviors of the alloy in two types of solutions were all dependent on the pre-immersion time.In the 9 g/L NaCl solution,the corrosion current densities of the alloy decreased firstly with the pre-immersion time being<4 h and then increased with the pre-immersion time prolonging from 4 to 48 h.However,in the 9 g/L NaCl solution containing with CaCl_(2) and NaHCO3,the corrosion current density of the alloy exhibited the adverse trend with the prolonging the pre-immersion time.Failure analysis demonstrated that the changes of corrosion resistance in two solutions were mainly dominated by the constituents formed in surface films.
