The microstructure evolution and mechanical properties of Mg−15.3Gd−1Zn alloys with different Al contents(0,0.4,0.7 and 1.0 wt.%)were investigated.Microstructural analysis indicates that the addition of 0.4 wt.%Al fac...The microstructure evolution and mechanical properties of Mg−15.3Gd−1Zn alloys with different Al contents(0,0.4,0.7 and 1.0 wt.%)were investigated.Microstructural analysis indicates that the addition of 0.4 wt.%Al facilitates the formation of 18R-LPSO phase(Mg12Gd(Al,Zn))in the Mg−Gd−Zn alloy.The contents of Al11Gd3 and Al2Gd increase with the increase of Al content,while the content of(Mg,Zn)_(3)Gd decreases.After homogenization treatment,(Mg,Zn)_(3)Gd,18R-LPSO and some Al11Gd3 phases are transformed into the high-temperature stable 14H-LPSO phases.The particulate Al−Gd phases can stimulate the nucleation of dynamic recrystallization by the particle simulated nucleation(PSN)mechanism.The tensile strength of the as-rolled alloys is improved remarkably due to the grain refinement and the fiber-like reinforcement of LPSO phase.The precipitation of theβ′phase in the peak-aged alloys can significantly improve the strength.The peak-aged alloy containing 0.4 wt.%Al achieves excellent mechanical properties and the UTS,YS and elongation are 458 MPa,375 MPa and 6.2%,respectively.展开更多
In this study,NbTaTiV refractory high-entropy alloys(RHEAs) reinforced with dispersed oxides were successfully designed and fabricated by mechanical alloying and subsequent spark plasma sintering(SPS).The effects of Y...In this study,NbTaTiV refractory high-entropy alloys(RHEAs) reinforced with dispersed oxides were successfully designed and fabricated by mechanical alloying and subsequent spark plasma sintering(SPS).The effects of Y_(2)O_(3) content on the microstructure and mechanical properties have been systematically studied.The results show that the oxide dispersion strengthening(ODS) RHEAs are mainly composed of body centered cubic(BCC) matrix and multiscale oxides,including submicron Ti-(N,O) particles,nano-sized Y-Ti-O particles and nano-sized Y_(2)O_(3) particles.The ODS-RHEAs have excellent mechanical properties due to the multisc ale oxides.With the content of Y_(2)O_(3) increasing from 1 wt% to 3 wt% Y_(2)O_(3),the compressive yield strength of the ODSRHEAs significantly increases from 1528 to 1866 MPa,while the fracture strain slightly reduces from 22% to 16%.The enhancement of the mechanical property is mainly attributed to the increased amount of multisc ale oxide particles and the refined grain structure.展开更多
基金the financial supports from the Natural Science Foundation of Hunan Province, China (No. 2018JJ2365)the Outstanding Youth Scientific Research Project of Hunan Education Department, China (No. 20B533)+3 种基金the Key Scientific Research Project of Hunan Provincial Department of Education, China (No. 20A455)the Science and Technology Innovation Program of Hunan Province, China (No. 2020RC1011)the Graduate Scientific Research Innovation Project of Hunan Province, China (No. CX20211280)the Science and Technology Innovation Leading Plan of High Tech Industry in Hunan Province, China (No. 2020GK2033)。
文摘The microstructure evolution and mechanical properties of Mg−15.3Gd−1Zn alloys with different Al contents(0,0.4,0.7 and 1.0 wt.%)were investigated.Microstructural analysis indicates that the addition of 0.4 wt.%Al facilitates the formation of 18R-LPSO phase(Mg12Gd(Al,Zn))in the Mg−Gd−Zn alloy.The contents of Al11Gd3 and Al2Gd increase with the increase of Al content,while the content of(Mg,Zn)_(3)Gd decreases.After homogenization treatment,(Mg,Zn)_(3)Gd,18R-LPSO and some Al11Gd3 phases are transformed into the high-temperature stable 14H-LPSO phases.The particulate Al−Gd phases can stimulate the nucleation of dynamic recrystallization by the particle simulated nucleation(PSN)mechanism.The tensile strength of the as-rolled alloys is improved remarkably due to the grain refinement and the fiber-like reinforcement of LPSO phase.The precipitation of theβ′phase in the peak-aged alloys can significantly improve the strength.The peak-aged alloy containing 0.4 wt.%Al achieves excellent mechanical properties and the UTS,YS and elongation are 458 MPa,375 MPa and 6.2%,respectively.
基金financially supported by the National Natural Science Foundation of China (Nos.51771232 and 52104365).
文摘In this study,NbTaTiV refractory high-entropy alloys(RHEAs) reinforced with dispersed oxides were successfully designed and fabricated by mechanical alloying and subsequent spark plasma sintering(SPS).The effects of Y_(2)O_(3) content on the microstructure and mechanical properties have been systematically studied.The results show that the oxide dispersion strengthening(ODS) RHEAs are mainly composed of body centered cubic(BCC) matrix and multiscale oxides,including submicron Ti-(N,O) particles,nano-sized Y-Ti-O particles and nano-sized Y_(2)O_(3) particles.The ODS-RHEAs have excellent mechanical properties due to the multisc ale oxides.With the content of Y_(2)O_(3) increasing from 1 wt% to 3 wt% Y_(2)O_(3),the compressive yield strength of the ODSRHEAs significantly increases from 1528 to 1866 MPa,while the fracture strain slightly reduces from 22% to 16%.The enhancement of the mechanical property is mainly attributed to the increased amount of multisc ale oxide particles and the refined grain structure.
