To explore the optimum use of stabilised elements and study the influences of stabilisation in 18 Cr-2 Mo grades,the Nb and Nb+Ti microalloying investigation focused on the relationships of the microstructure and mech...To explore the optimum use of stabilised elements and study the influences of stabilisation in 18 Cr-2 Mo grades,the Nb and Nb+Ti microalloying investigation focused on the relationships of the microstructure and mechanical properties of the microalloyed 18 Cr-2 Mo ferritic stainless steel thick plates.Thermo-Calc calculation was performed to predict the equilibrium phase diagrams.Afterwards,the microstructure,i.e.grain size and precipitation,of as-annealed specimens was analysed by means of optical microscopy,scanning electron microscopy and transmission electron microscopy,X-ray diffraction and energydispersive spectroscopy.Also,electron backscatter diffraction mapping was constructed to characterise grain boundary.The mechanical properties,including tensile strength and impact toughness,were tested to correlate with the microstructure.The results show that the grain sizes of Nb-stabilised steel are comparatively smaller,which is related to the fine precipitation at the grain boundaries and beneficial to the impact toughness.The increase in its strength is not apparent due to the inhomogeneous grain sizes.The grain boundary characters are similar,which is not the main factor related to their mechanical properties.When Ti is added,TiN forms above the liquidus,and large TiN particles evidently impair impact toughness.展开更多
To enhance the stress corrosion cracking(SCC)resistance,Zn was utilized as an alloy element to add in the AA5083 aluminum alloys.The effects of Zn content on the microstructures,mechanical properties and SCC resistanc...To enhance the stress corrosion cracking(SCC)resistance,Zn was utilized as an alloy element to add in the AA5083 aluminum alloys.The effects of Zn content on the microstructures,mechanical properties and SCC resistance were systematically evaluated.The results demonstrate that in the studied range adding Zn can significantly improve the SCC resistance of the AA5083 alloys.This is related to the relatively low amount of continuous β(Al3Mg2)phase along grain boundary and the formation of Zn-containing phase such as Al5Mg11Zn4 phase.Based on the results,the optimal Zn content with respect to SCC resistance is approximately 0.50 wt.%.Further increasing Zn content results in coarse precipitates discontinuously distributed along grain boundaries.展开更多
文摘To explore the optimum use of stabilised elements and study the influences of stabilisation in 18 Cr-2 Mo grades,the Nb and Nb+Ti microalloying investigation focused on the relationships of the microstructure and mechanical properties of the microalloyed 18 Cr-2 Mo ferritic stainless steel thick plates.Thermo-Calc calculation was performed to predict the equilibrium phase diagrams.Afterwards,the microstructure,i.e.grain size and precipitation,of as-annealed specimens was analysed by means of optical microscopy,scanning electron microscopy and transmission electron microscopy,X-ray diffraction and energydispersive spectroscopy.Also,electron backscatter diffraction mapping was constructed to characterise grain boundary.The mechanical properties,including tensile strength and impact toughness,were tested to correlate with the microstructure.The results show that the grain sizes of Nb-stabilised steel are comparatively smaller,which is related to the fine precipitation at the grain boundaries and beneficial to the impact toughness.The increase in its strength is not apparent due to the inhomogeneous grain sizes.The grain boundary characters are similar,which is not the main factor related to their mechanical properties.When Ti is added,TiN forms above the liquidus,and large TiN particles evidently impair impact toughness.
基金financially supported by the Nature Science Research Project of Anhui Province(No.1808085QE136)the Anhui Postdoctoral Science Foundation(No.934269)the National Natural Science Foundation of China(No.51905143)。
文摘To enhance the stress corrosion cracking(SCC)resistance,Zn was utilized as an alloy element to add in the AA5083 aluminum alloys.The effects of Zn content on the microstructures,mechanical properties and SCC resistance were systematically evaluated.The results demonstrate that in the studied range adding Zn can significantly improve the SCC resistance of the AA5083 alloys.This is related to the relatively low amount of continuous β(Al3Mg2)phase along grain boundary and the formation of Zn-containing phase such as Al5Mg11Zn4 phase.Based on the results,the optimal Zn content with respect to SCC resistance is approximately 0.50 wt.%.Further increasing Zn content results in coarse precipitates discontinuously distributed along grain boundaries.
