In our previous work,die cast LA42(Mg-4La-2.5Al-0.3Mn,wt.%)alloy with an excellent combination of thermal-conducting performance and mechanical properties was developed.This study,taking commercial die cast AZ91(Mg-9A...In our previous work,die cast LA42(Mg-4La-2.5Al-0.3Mn,wt.%)alloy with an excellent combination of thermal-conducting performance and mechanical properties was developed.This study,taking commercial die cast AZ91(Mg-9Al-1 Zn,wt.%)alloy as a comparison,investigates the microstructure and corrosion behavior of the LA42 alloy in chloride-containing environment.The findings revealed that the microstructure of die cast LA42 alloy displays an Al-depletedα-Mg dendrite and a network shape eutectic phase comprising of eutecticα-Mg and lamellar Al11La3.The LA42 alloy exhibited slightly inferior corrosion resistance and deeper corrosion pits than the AZ91 alloy,which were related to the interphase attack and the presence of a layer of corrosion products containing more magnesium hydroxide of the LA42alloy.The corrosion behavior of the LA42 alloy was characterized by an interphase attack on the periphery of Al-depletedα-Mg dendrite adjacent to Al_(11)La_(3),which primarily ascribed to the relatively lower potential of the Al-depletedα-Mg phase and the interfacial reactivity between it and the adjacent Al_(11)La_(3),whereas the AZ91 alloy showed a trait of preferential corrosion of the interior ofα-Mg dendrite for its lowest potential among different phases.This comprehensive research can provide a guidance for future alloy design of Mg-Al-La alloys and their industrial applications.展开更多
For alloy Ti-24Al-11Nb,stress corrosion cracking(SCC) in methanol solution and hydrogen induced cracking(HIC) during dynamic charging at room temperature have been studied.Experiment has shown that the normalised thre...For alloy Ti-24Al-11Nb,stress corrosion cracking(SCC) in methanol solution and hydrogen induced cracking(HIC) during dynamic charging at room temperature have been studied.Experiment has shown that the normalised threshold stress intensities of SCC failure for various microstructures are KISCC/KC =0.53 0.69 and the threshold value for SCC arresting KISCC/ KIC=0.61-0.79.The threshold values of HIC during dynamic charging are close to that of SCC,but da/dt or fracture time of HIC is one to three orders of magnitude smaller or longer than that of SCC,respectively.The.fracture surface for HIC is also different from that for SCC.For the Ti-24Al-Nb alloy-methanol systein,a kind of inierphase SCC has been found For the microstructures resulting from furnace cooling,SCC initiated and propagated preferentially along theα2/βinterphase boundaries,displaying the microstructure on the fracture surface of SCC.However,there is no interphase SCC for the microstructure resulting from air cooling.展开更多
基金supports from the collaboration research item between Shanghai Jiao Tong University and Hitachi(China)Ltdsupported by Qinghai Salt Lake Industry Co.Ltd financially by via of the Science and Technology Project(21-ZC0609-0003)the National Natural Science Foundation of China(No.51825101)。
文摘In our previous work,die cast LA42(Mg-4La-2.5Al-0.3Mn,wt.%)alloy with an excellent combination of thermal-conducting performance and mechanical properties was developed.This study,taking commercial die cast AZ91(Mg-9Al-1 Zn,wt.%)alloy as a comparison,investigates the microstructure and corrosion behavior of the LA42 alloy in chloride-containing environment.The findings revealed that the microstructure of die cast LA42 alloy displays an Al-depletedα-Mg dendrite and a network shape eutectic phase comprising of eutecticα-Mg and lamellar Al11La3.The LA42 alloy exhibited slightly inferior corrosion resistance and deeper corrosion pits than the AZ91 alloy,which were related to the interphase attack and the presence of a layer of corrosion products containing more magnesium hydroxide of the LA42alloy.The corrosion behavior of the LA42 alloy was characterized by an interphase attack on the periphery of Al-depletedα-Mg dendrite adjacent to Al_(11)La_(3),which primarily ascribed to the relatively lower potential of the Al-depletedα-Mg phase and the interfacial reactivity between it and the adjacent Al_(11)La_(3),whereas the AZ91 alloy showed a trait of preferential corrosion of the interior ofα-Mg dendrite for its lowest potential among different phases.This comprehensive research can provide a guidance for future alloy design of Mg-Al-La alloys and their industrial applications.
文摘For alloy Ti-24Al-11Nb,stress corrosion cracking(SCC) in methanol solution and hydrogen induced cracking(HIC) during dynamic charging at room temperature have been studied.Experiment has shown that the normalised threshold stress intensities of SCC failure for various microstructures are KISCC/KC =0.53 0.69 and the threshold value for SCC arresting KISCC/ KIC=0.61-0.79.The threshold values of HIC during dynamic charging are close to that of SCC,but da/dt or fracture time of HIC is one to three orders of magnitude smaller or longer than that of SCC,respectively.The.fracture surface for HIC is also different from that for SCC.For the Ti-24Al-Nb alloy-methanol systein,a kind of inierphase SCC has been found For the microstructures resulting from furnace cooling,SCC initiated and propagated preferentially along theα2/βinterphase boundaries,displaying the microstructure on the fracture surface of SCC.However,there is no interphase SCC for the microstructure resulting from air cooling.
