The development of alloys with high antioxidation performance is limited by the ambiguous details of the oxidation mechanism.Here,based on the structures of internal oxides detected by high-resolution transmission ele...The development of alloys with high antioxidation performance is limited by the ambiguous details of the oxidation mechanism.Here,based on the structures of internal oxides detected by high-resolution transmission electron microscopy,a hybrid method combining first-principles calculation,climb image nudged elastic band method and quasi-harmonic Debye model has been implemented to explain the oxidation mechanism with an emphasis on the origin of delamination and cracking.The results showed that the delamination of oxides corresponds to the acceleration of diffusion of Cr element caused by lamellar structures.The reduction in the cracking occurrence at high temperature mainly results from the smaller bulk modulus of oxides.Furthermore,the stronger chemical bonds promoted by lamellar structures also correspond to the higher crackingresistance.展开更多
The effect of Zr addition(0.005,0.013,and 0.054 wt.%)on the microstructure and toughness of simulated coarse-grained heat-affected zone in high-strength low-alloy steels was revealed using a Gleeble 2000 thermal simul...The effect of Zr addition(0.005,0.013,and 0.054 wt.%)on the microstructure and toughness of simulated coarse-grained heat-affected zone in high-strength low-alloy steels was revealed using a Gleeble 2000 thermal simulator.It was observed that elongated MnS inclusions were formed in the lowest Zr-containing steel,while only pure equiaxed ZrO2 existed in the 0.054Zr steel(Zr content of 0.054 wt.%).Complex oxide-sulfide inclusions(ZrO2+MnS)with size of(1.40±0.25)μtm were formed in 0.013Zr steel(Zr content of 0.013 wt.%).The complex inclusions refined the prior austenite grain,and the nucleation of acicular ferrite was promoted compared to those of 0.005Zr steel(Zr content of 0.005 wt.%)and 0.054Zr steel.Consequently,the 0.013Zr steel possessed superior low-temperature impact toughness in relation to 0.005Zr and 0.054Zr steels.Thus,moderate Zr addition can be considered as an effective method to refine the structure and improve the mechanical properties of the coarse-grained heat-affected zone.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.12174296,U20A20279,U1532268,U1932134 and U1867215)the Key Research and Development Program of Hubei Province(Grant No.2021BAA057)+2 种基金Hubei Provincial Colleges and Universities Excellent Young and Middle-aged Science and Technology Innovation Team Project(Grant No.T201903)Wuhan City Applied Basic Frontier Project(Grant No.2019010701011382)Wuhan University of Science and Technology Graduate Innovation and Entrepreneurship Fund(Grant No.JCX2021094)and 111 Project(Grant No.2018018)。
文摘The development of alloys with high antioxidation performance is limited by the ambiguous details of the oxidation mechanism.Here,based on the structures of internal oxides detected by high-resolution transmission electron microscopy,a hybrid method combining first-principles calculation,climb image nudged elastic band method and quasi-harmonic Debye model has been implemented to explain the oxidation mechanism with an emphasis on the origin of delamination and cracking.The results showed that the delamination of oxides corresponds to the acceleration of diffusion of Cr element caused by lamellar structures.The reduction in the cracking occurrence at high temperature mainly results from the smaller bulk modulus of oxides.Furthermore,the stronger chemical bonds promoted by lamellar structures also correspond to the higher crackingresistance.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.51671149)Wuhan Science and Technology Program(Grant No.2019010701011382)+1 种基金Major Technology Innovation of Hubei Province(2016AAA022)111 Project.R.D.K.Misra gratefully acknowledges continued collaboration with WUST as Guest Professor.
文摘The effect of Zr addition(0.005,0.013,and 0.054 wt.%)on the microstructure and toughness of simulated coarse-grained heat-affected zone in high-strength low-alloy steels was revealed using a Gleeble 2000 thermal simulator.It was observed that elongated MnS inclusions were formed in the lowest Zr-containing steel,while only pure equiaxed ZrO2 existed in the 0.054Zr steel(Zr content of 0.054 wt.%).Complex oxide-sulfide inclusions(ZrO2+MnS)with size of(1.40±0.25)μtm were formed in 0.013Zr steel(Zr content of 0.013 wt.%).The complex inclusions refined the prior austenite grain,and the nucleation of acicular ferrite was promoted compared to those of 0.005Zr steel(Zr content of 0.005 wt.%)and 0.054Zr steel.Consequently,the 0.013Zr steel possessed superior low-temperature impact toughness in relation to 0.005Zr and 0.054Zr steels.Thus,moderate Zr addition can be considered as an effective method to refine the structure and improve the mechanical properties of the coarse-grained heat-affected zone.
