Generally,bulk metallic glasses(BMGs)exhibit a very limited plastic deformation under a compression load at room temperature,often less than 2% before fracturing.In this letter,through an appropriate choice of BMGs...Generally,bulk metallic glasses(BMGs)exhibit a very limited plastic deformation under a compression load at room temperature,often less than 2% before fracturing.In this letter,through an appropriate choice of BMGs' composition,an amorphous rod of Zr64.80Cu14.85Ni10.35Al10 with a diameter of 2 mm was prepared by using copper mold suction casting.X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal stability,and the uniaxial compression test was adopted to study its plastic deformation behavior at room temperature simultaneously.The results showed that the glass transition temperature and onset temperature of the exothermic reaction of the amorphous rod were 646 and 750 K,respectively,and its micro-hardness was 594.7 Hv.During com-pression,when the engineering strain and engineering stress arrived at 9.05% and 1732 MPa,respec-tively,i.e.,the true strain and true stress reached 9.42% and 1560 MPa,respectively,the amorphous rod started to yield.After yielding,with the increase of load,the strain increased and the glass rod ulti-mately were compressed into flake-like form.Although the maximum engineering strain was larger than 70%,i.e.,the maximum true strain exceeded by 120%,the amorphous specimen was not fractured,indicating that it has super-plasticity at room temperature.Through the appropriate choice of compo-sition and optimization of the technological process,flexible BMG with super-plasticity at room tem-perature could be produced.展开更多
To explore ambient strengthening and high temperature ductility,a combined forming approach of multidirectional forging and asymmetric rolling was proposed.A novel multicomponent ultralight Mg-3.11Li-2.31Al-1.95Sn-0.9...To explore ambient strengthening and high temperature ductility,a combined forming approach of multidirectional forging and asymmetric rolling was proposed.A novel multicomponent ultralight Mg-3.11Li-2.31Al-1.95Sn-0.94Y-0.45Er alloy was fabricated.The microstructural evolution and mechanical properties were investigated by microstructural characterization and tensile test.The combined forming results in remarkable grain refinement.The ultimate tensile strength and elongation of(255±7)MPa and 24.9%,respectively,were obtained at room temperature.The contribution of various strengthening mechanisms of the rolled alloy was obtained.Microstructural examination revealed the occurrence of dynamic recrystallization at 473-573 K and dynamic grain growth at 573-623 K.The maximum elongation of 293.9%was demonstrated at 623 K and 5×10^(-4)s^(-1).The dominate deformation mechanism at elevated temperatures is dislocation viscous glide.展开更多
基金the National Natural Sciences Foundation of China(Grant Nos.50771077 and 50371020)the Natural Science Foundation of Guangdong Prov-ince,China(Grant No.06021473)
文摘Generally,bulk metallic glasses(BMGs)exhibit a very limited plastic deformation under a compression load at room temperature,often less than 2% before fracturing.In this letter,through an appropriate choice of BMGs' composition,an amorphous rod of Zr64.80Cu14.85Ni10.35Al10 with a diameter of 2 mm was prepared by using copper mold suction casting.X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal stability,and the uniaxial compression test was adopted to study its plastic deformation behavior at room temperature simultaneously.The results showed that the glass transition temperature and onset temperature of the exothermic reaction of the amorphous rod were 646 and 750 K,respectively,and its micro-hardness was 594.7 Hv.During com-pression,when the engineering strain and engineering stress arrived at 9.05% and 1732 MPa,respec-tively,i.e.,the true strain and true stress reached 9.42% and 1560 MPa,respectively,the amorphous rod started to yield.After yielding,with the increase of load,the strain increased and the glass rod ulti-mately were compressed into flake-like form.Although the maximum engineering strain was larger than 70%,i.e.,the maximum true strain exceeded by 120%,the amorphous specimen was not fractured,indicating that it has super-plasticity at room temperature.Through the appropriate choice of compo-sition and optimization of the technological process,flexible BMG with super-plasticity at room tem-perature could be produced.
基金supported by the National Natural Science Foundation of China(No.51334006)。
文摘To explore ambient strengthening and high temperature ductility,a combined forming approach of multidirectional forging and asymmetric rolling was proposed.A novel multicomponent ultralight Mg-3.11Li-2.31Al-1.95Sn-0.94Y-0.45Er alloy was fabricated.The microstructural evolution and mechanical properties were investigated by microstructural characterization and tensile test.The combined forming results in remarkable grain refinement.The ultimate tensile strength and elongation of(255±7)MPa and 24.9%,respectively,were obtained at room temperature.The contribution of various strengthening mechanisms of the rolled alloy was obtained.Microstructural examination revealed the occurrence of dynamic recrystallization at 473-573 K and dynamic grain growth at 573-623 K.The maximum elongation of 293.9%was demonstrated at 623 K and 5×10^(-4)s^(-1).The dominate deformation mechanism at elevated temperatures is dislocation viscous glide.
