Zr-based metallic glasses(MGs)possess a wide supercooled liquid region,which gives a wide processing window for superplastic forming to make microdevices with demanding size accuracy and surface finishing.The existenc...Zr-based metallic glasses(MGs)possess a wide supercooled liquid region,which gives a wide processing window for superplastic forming to make microdevices with demanding size accuracy and surface finishing.The existence of oxygen may have an influence on the thermoplastic deformation process.Therefore,the effect of oxidation on the mechanical behavior of the MGs in the vicinity of glass transition temperature is of great significance for practical forming of MG components.In the present study,the effect of oxidation on tensile properties of Zr50Cu40Al10 metallic glass was investigated.The tested samples were characterized by XRD and SEM analysis.For the samples tested in air,the strength decreases 187 MPa,61 MPa and 59 MPa and the ductility increases 0.31,0.36,and 0.77 at 420℃,430℃,and 440℃,respectively,compared with those tested in flowing argon.ZrO_(2) preferentially formed during the tensile testing at 420℃,and both ZrO_(2) and Al_(2)O_(3) oxides formed at 430℃.The dilution of Zr elements in the remaining amorphous matrix caused by preferential oxidation on the surface layer attributes to the decrease in strength and enhancement in ductility of the Zr_(50)Cu_(40)Al_(10) metallic glasses.展开更多
The elevated temperature performances of 2D70 Al alloy hot extrusion rods after two-stage homogenization and intensive deformation were studied by measuring the elevated temperature enduring strength and the creep ult...The elevated temperature performances of 2D70 Al alloy hot extrusion rods after two-stage homogenization and intensive deformation were studied by measuring the elevated temperature enduring strength and the creep ultimate strength. The fracture morphology of some selected samples after testing at different elevated temperatures was observed by scanning electron microscopy （SEM）. The results indicate that, as the test temperature increases, the elevated temperature enduring strength of 2D70 Al alloy decreases gradually. In a comparison between 150 C and 240 C, the notch enduring strength drops from 375 to 185 MPa and the smooth enduring strength drops from 337 to 130 MPa. Enduring strength is not sensitive to the notch. The notch sensitivity ratio （NSR） coefficient is in the range of 1.119 to 1.423 from 150 C to 240 C. The creep test results show that, as the test temperature increases from 150 C to 240 C, the creep ultimate strength of 2D70 Al alloy rods drops gradually from 312 to 117 MPa.展开更多
This article focuses on the tensile and compressive characteristics of a Ti-based bulk metallic glass composite （BMGC）. It is found that the yield stress, maximum strength, and fracture strain are 1380 MPa, 1516 MPa...This article focuses on the tensile and compressive characteristics of a Ti-based bulk metallic glass composite （BMGC）. It is found that the yield stress, maximum strength, and fracture strain are 1380 MPa, 1516 MPa, and 4.3% for uniaxial tension, but 1580 MPa, 4010 MPa, and 29% for uniaxial compression, respectively. The composite displays a linear ＂work hardening＂ capacity under compression; however, the ＂work softening＂ behavior is observed in the true engineering stress-strain curve upon tensile loading. The fracture surfaces of specimens also exhibit dissimilar properties under the different loadings.展开更多
基金financially supported by the National Natural Science Foundation of China(Grant No.51801208)the Joint Research Fund of Natural Science Foundation of Liaoning Province-State Key Laboratory of Rolling and Automation(Grant No.2019-KF-05-05)。
文摘Zr-based metallic glasses(MGs)possess a wide supercooled liquid region,which gives a wide processing window for superplastic forming to make microdevices with demanding size accuracy and surface finishing.The existence of oxygen may have an influence on the thermoplastic deformation process.Therefore,the effect of oxidation on the mechanical behavior of the MGs in the vicinity of glass transition temperature is of great significance for practical forming of MG components.In the present study,the effect of oxidation on tensile properties of Zr50Cu40Al10 metallic glass was investigated.The tested samples were characterized by XRD and SEM analysis.For the samples tested in air,the strength decreases 187 MPa,61 MPa and 59 MPa and the ductility increases 0.31,0.36,and 0.77 at 420℃,430℃,and 440℃,respectively,compared with those tested in flowing argon.ZrO_(2) preferentially formed during the tensile testing at 420℃,and both ZrO_(2) and Al_(2)O_(3) oxides formed at 430℃.The dilution of Zr elements in the remaining amorphous matrix caused by preferential oxidation on the surface layer attributes to the decrease in strength and enhancement in ductility of the Zr_(50)Cu_(40)Al_(10) metallic glasses.
基金support from the National Key Technology Research and Development Program of China (No.2007BAE38B06)Heilongjiang Province Science Fund for Distinguished Young Scholars(No. JC201013)
文摘The elevated temperature performances of 2D70 Al alloy hot extrusion rods after two-stage homogenization and intensive deformation were studied by measuring the elevated temperature enduring strength and the creep ultimate strength. The fracture morphology of some selected samples after testing at different elevated temperatures was observed by scanning electron microscopy （SEM）. The results indicate that, as the test temperature increases, the elevated temperature enduring strength of 2D70 Al alloy decreases gradually. In a comparison between 150 C and 240 C, the notch enduring strength drops from 375 to 185 MPa and the smooth enduring strength drops from 337 to 130 MPa. Enduring strength is not sensitive to the notch. The notch sensitivity ratio （NSR） coefficient is in the range of 1.119 to 1.423 from 150 C to 240 C. The creep test results show that, as the test temperature increases from 150 C to 240 C, the creep ultimate strength of 2D70 Al alloy rods drops gradually from 312 to 117 MPa.
基金supports by the National Natural Science Foundation of China(No.51001008)the Fundamental Research Funds for the Central Universities of China(FRF-MP-10-005B)
文摘This article focuses on the tensile and compressive characteristics of a Ti-based bulk metallic glass composite （BMGC）. It is found that the yield stress, maximum strength, and fracture strain are 1380 MPa, 1516 MPa, and 4.3% for uniaxial tension, but 1580 MPa, 4010 MPa, and 29% for uniaxial compression, respectively. The composite displays a linear ＂work hardening＂ capacity under compression; however, the ＂work softening＂ behavior is observed in the true engineering stress-strain curve upon tensile loading. The fracture surfaces of specimens also exhibit dissimilar properties under the different loadings.
