As-east mierostruetures and their distribution of Mg-Zn-Y ternary alloy with high magnesium, low zinc and yttrium were examined using Nikon Epiphot optical microscopy （OM）, RigakuD/max-3C X- ray diffraetion （XRD）,...As-east mierostruetures and their distribution of Mg-Zn-Y ternary alloy with high magnesium, low zinc and yttrium were examined using Nikon Epiphot optical microscopy （OM）, RigakuD/max-3C X- ray diffraetion （XRD）, and JEOL JSM-6700F scanning electron microscopy （SEM） equipped with an energydispersive X-ray spectroscopy （EDS）. In the as-east mierostructures, Yttrium and zinc tend to segregate at grain boundaries,展开更多
Mg68Zn28Y4 alloys with stable icosahedral quasicrystals(Zn60Mg30Y10)were prepared by cast method.By simulating the environment of ocean,the alloy was eroded in 3.5%(mass fraction)NaCl for 2,4 and 30 h.The microstructu...Mg68Zn28Y4 alloys with stable icosahedral quasicrystals(Zn60Mg30Y10)were prepared by cast method.By simulating the environment of ocean,the alloy was eroded in 3.5%(mass fraction)NaCl for 2,4 and 30 h.The microstructures of the samples and eroded alloys were analyzed by OM and SEM.The compositions and the quasiperiodic structures were identified respectively by EDS and TEM.And the corrosion potential and corrosion current density before and after immersion were measured by potentiodynamic polarization measurements in 3.5%NaCl.The results show that I-phases grow in the mode of conglomeration, piling and transfixion.The Mg7Zn3 matrix andα(Mg)solid solution are eroded badly,while W-phase is eroded partially.At the same time,the I-phases exhibit excellent corrosion resistance property.The resistance to corrosion of Mg68Zn28Y4 alloy is improved by increasing exposed I-phases.With adding element Y to Mg68Zn32 alloy,the corrosion current is decreased by one order of magnitude. And after the immersion of as-cast Mg68Zn28Y4 alloy for 30 h,the corrosion current density is reduced by two orders of magnitude compared with that of uneroded Mg68Zn32 alloy.展开更多
1.IntroductionMedium Mn steel was developed be-cause the wear resistance of Hadfield steel(Mn13)is poor under low or medium im-pact and extrusion abrasion[1-4].In theforegoing investigations[2-4]we found thatwith the ...1.IntroductionMedium Mn steel was developed be-cause the wear resistance of Hadfield steel(Mn13)is poor under low or medium im-pact and extrusion abrasion[1-4].In theforegoing investigations[2-4]we found thatwith the increase of C content,theneedle-like and network carbide in mediumMn steel increased(as shown in Fig.1(a)and(c)).Although its wear resistance was largelyimproved,its impact toughness was greatlydecreased.In order to increase toughness,along-term high temperature heat-treatmentwas needed.But the treatment caused cracks展开更多
文摘As-east mierostruetures and their distribution of Mg-Zn-Y ternary alloy with high magnesium, low zinc and yttrium were examined using Nikon Epiphot optical microscopy （OM）, RigakuD/max-3C X- ray diffraetion （XRD）, and JEOL JSM-6700F scanning electron microscopy （SEM） equipped with an energydispersive X-ray spectroscopy （EDS）. In the as-east mierostructures, Yttrium and zinc tend to segregate at grain boundaries,
基金Project(50271054)supported by the National Natural Science Foundation of ChinaProject(2002E110)supported by the Natural Science Foundation of Shannxi Province,ChinaProject supported by the Scientific Research Foundation of the Education Department of Shaanxi Province for the Returned Overseas Chinese Scholars
文摘Mg68Zn28Y4 alloys with stable icosahedral quasicrystals(Zn60Mg30Y10)were prepared by cast method.By simulating the environment of ocean,the alloy was eroded in 3.5%(mass fraction)NaCl for 2,4 and 30 h.The microstructures of the samples and eroded alloys were analyzed by OM and SEM.The compositions and the quasiperiodic structures were identified respectively by EDS and TEM.And the corrosion potential and corrosion current density before and after immersion were measured by potentiodynamic polarization measurements in 3.5%NaCl.The results show that I-phases grow in the mode of conglomeration, piling and transfixion.The Mg7Zn3 matrix andα(Mg)solid solution are eroded badly,while W-phase is eroded partially.At the same time,the I-phases exhibit excellent corrosion resistance property.The resistance to corrosion of Mg68Zn28Y4 alloy is improved by increasing exposed I-phases.With adding element Y to Mg68Zn32 alloy,the corrosion current is decreased by one order of magnitude. And after the immersion of as-cast Mg68Zn28Y4 alloy for 30 h,the corrosion current density is reduced by two orders of magnitude compared with that of uneroded Mg68Zn32 alloy.
文摘1.IntroductionMedium Mn steel was developed be-cause the wear resistance of Hadfield steel(Mn13)is poor under low or medium im-pact and extrusion abrasion[1-4].In theforegoing investigations[2-4]we found thatwith the increase of C content,theneedle-like and network carbide in mediumMn steel increased(as shown in Fig.1(a)and(c)).Although its wear resistance was largelyimproved,its impact toughness was greatlydecreased.In order to increase toughness,along-term high temperature heat-treatmentwas needed.But the treatment caused cracks
基金National Natural Science Foundation of China(51164015)Science and Technology Innovation Team of Kunming City(2012-01-01-A-R-07-0005)+1 种基金Scientific and Technological Cooperative Project(2012IB002)Key Basic Research Project of Yunnan Province(2011FA026)
