Corrosion resistance behavior of Co-containing maraging stainless steels was investigated. Neutral salt spray and polarization test showed that maraging stainless steel with high Co content showed poor corrosion behav...Corrosion resistance behavior of Co-containing maraging stainless steels was investigated. Neutral salt spray and polarization test showed that maraging stainless steel with high Co content showed poor corrosion behavior. Microstructure observation proved that segregation of Cr in the matrix deteriorated its corrosion resistance. The surface morphology of the aged maraging stainless steel with high Co content indicated that during passivation process, the newly formed passive film with sinusoidal distribution readily destroyed by the corrosive medium, hence, causing poor corrosion resistance. Moreover, through first-principles calculation it was proved that Co increased Fe–Fe ferromagnetic interaction which facilitated the formation Cr-rich clusters.展开更多
Precipitates,including silicides and Ti3 Al(α2)phase,and alloying elements distribution in a near a titanium alloy Ti65(Ti-5.8 Al-4.0 Sn-3.5 Zr-0.5 Mo-0.3 Nb-1.0 Ta-0.4 Si-0.8 W-0.05 C)after solution treatment and ag...Precipitates,including silicides and Ti3 Al(α2)phase,and alloying elements distribution in a near a titanium alloy Ti65(Ti-5.8 Al-4.0 Sn-3.5 Zr-0.5 Mo-0.3 Nb-1.0 Ta-0.4 Si-0.8 W-0.05 C)after solution treatment and aging process were characterized by using transmission electron microscopy(TEM)and atom probe tomography(APT).Quantitative composition analysis and TEM observation indicate that the silicides fit to(Ti,Zr)6(Sl,Sn)3.Zr exhibits aβ-stabilizing effect in near a titanium alloys but is weaker than otherβstabilizing elements.The enriching tendency of the alloying elements in the retainedβphase is in the order of Zr<Nb<Ta<Mo<W.The experimental results are rationalized by the relative stability of alloying elements in the a andβphases and the mobility of these atoms in the matrix.An enrichment of Si in theα2 phase over theαmatrix phase is noticed,which is attributed to the lower formation energy of Si in theα2 phase.展开更多
The effect of Co addition on the formation of Ni-Ti clusters in maraging stainless steel was studied by three dimensional atom probe（3 DAP） and first-principles calculation. The cluster analysis based on the maximum...The effect of Co addition on the formation of Ni-Ti clusters in maraging stainless steel was studied by three dimensional atom probe（3 DAP） and first-principles calculation. The cluster analysis based on the maximum separation approach showed an increase in size but a decrease in density of Ni-Ti clusters with increasing the Co content. The first-principles calculation indicated weaker Co-Ni（Co-Ti） interactions than Co-Ti（Fe-Ti） interactions, which should be the essential reason for the change of distribution characteristics of Ni-Ti clusters in bcc Fe caused by Co addition.展开更多
基金sponsored by the Youth Innovation Promotion Association of Chinese Academy of Sciences (No. 2017233)the Innovation Project of Institute of Metal Research (No. 2015-ZD04)
文摘Corrosion resistance behavior of Co-containing maraging stainless steels was investigated. Neutral salt spray and polarization test showed that maraging stainless steel with high Co content showed poor corrosion behavior. Microstructure observation proved that segregation of Cr in the matrix deteriorated its corrosion resistance. The surface morphology of the aged maraging stainless steel with high Co content indicated that during passivation process, the newly formed passive film with sinusoidal distribution readily destroyed by the corrosive medium, hence, causing poor corrosion resistance. Moreover, through first-principles calculation it was proved that Co increased Fe–Fe ferromagnetic interaction which facilitated the formation Cr-rich clusters.
基金The authors acknowledge the helpful suggestions from Prof.Shangzhou Zhang and Dr.Yujing Liu.And TEM experimental assistance is kindly provided by Jiao Liu.
文摘Precipitates,including silicides and Ti3 Al(α2)phase,and alloying elements distribution in a near a titanium alloy Ti65(Ti-5.8 Al-4.0 Sn-3.5 Zr-0.5 Mo-0.3 Nb-1.0 Ta-0.4 Si-0.8 W-0.05 C)after solution treatment and aging process were characterized by using transmission electron microscopy(TEM)and atom probe tomography(APT).Quantitative composition analysis and TEM observation indicate that the silicides fit to(Ti,Zr)6(Sl,Sn)3.Zr exhibits aβ-stabilizing effect in near a titanium alloys but is weaker than otherβstabilizing elements.The enriching tendency of the alloying elements in the retainedβphase is in the order of Zr<Nb<Ta<Mo<W.The experimental results are rationalized by the relative stability of alloying elements in the a andβphases and the mobility of these atoms in the matrix.An enrichment of Si in theα2 phase over theαmatrix phase is noticed,which is attributed to the lower formation energy of Si in theα2 phase.
基金sponsored by Youth Innovation Promotion Association of Chinese Academy of Sciences (2017233)National Natural Science Foundation of C hina (No. 51472249)+2 种基金Innovation Project of Institute of Metal Research (2015-ZD04)National Natural Science Foundation of China Research Fund for International Young Scientists (No. 51750110515)the Special Program for Applied Research on Super Computation of the NSFCGuangdong Joint Fund (second phase) under Grant No. U1501501
文摘The effect of Co addition on the formation of Ni-Ti clusters in maraging stainless steel was studied by three dimensional atom probe（3 DAP） and first-principles calculation. The cluster analysis based on the maximum separation approach showed an increase in size but a decrease in density of Ni-Ti clusters with increasing the Co content. The first-principles calculation indicated weaker Co-Ni（Co-Ti） interactions than Co-Ti（Fe-Ti） interactions, which should be the essential reason for the change of distribution characteristics of Ni-Ti clusters in bcc Fe caused by Co addition.
