The fracture behaviour and morphologies of high-strength boron steel were investigated at different temperatures at a constant strain rate of 0.1 s-1 based on isothermal tensile tests. Fracture mechanisms were also an...The fracture behaviour and morphologies of high-strength boron steel were investigated at different temperatures at a constant strain rate of 0.1 s-1 based on isothermal tensile tests. Fracture mechanisms were also analyzed based on the relationship between microstructure transformation and continuous cooling transformation(CCT) curves. It is found that 1) fractures of the investigated steel at high temperatures are dimple fractures; 2) the deformation of high-strength boron steel at high temperatures accelerates diffusion transformations; thus, to obtain full martensite, a higher cooling rate is needed; and 3) the investigated steel has the best plasticity when the deformation temperature is 750 °C.展开更多
Needle-like crystals consisting of a solid solution of C(60)-C(70)fullerene were synthesized by a liquid-liquid interfacial precipitation method using toluene and 2-propanol as solvents.A machined crystal with a V-not...Needle-like crystals consisting of a solid solution of C(60)-C(70)fullerene were synthesized by a liquid-liquid interfacial precipitation method using toluene and 2-propanol as solvents.A machined crystal with a V-notch was placed in a focused ion beam scanning electron microscope where it was bent until fracture by pushing it with a molybdenum probe to measure its mechanical properties and its fracture surface was examined.The crystals had a tensile strength of 58-71 MPa,which is much higher than C60 fullerene needle-like crystals and slightly larger than alumina,and a fracture toughness of 1.1-1.3 MPa m(1/2).Moreover,it is possible to change the plasticity and fracture toughness of the C(60)-C(70)crystals by solvation of different numbers of fullerene molecules.The C(60)-C(70)fullerene crystals have the potential for use as electrodes,anchors for brittle materials,and ductile wires to carry electricity.展开更多
基金Project(51305317)supported by the National Natural Science Foundation of ChinaProjects(WUT:2013-IV-092,WUT:2014-VII-002)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(IRT13087)supported by Innovative Research Team Development Program of Ministry of Education of China
文摘The fracture behaviour and morphologies of high-strength boron steel were investigated at different temperatures at a constant strain rate of 0.1 s-1 based on isothermal tensile tests. Fracture mechanisms were also analyzed based on the relationship between microstructure transformation and continuous cooling transformation(CCT) curves. It is found that 1) fractures of the investigated steel at high temperatures are dimple fractures; 2) the deformation of high-strength boron steel at high temperatures accelerates diffusion transformations; thus, to obtain full martensite, a higher cooling rate is needed; and 3) the investigated steel has the best plasticity when the deformation temperature is 750 °C.
基金partly supported by the Center of Materials Research for Low Carbon Emission of National Institute for Materials Sciencethe Japan Society for the Promotion of Science KAKENHI(No.26600007)
文摘Needle-like crystals consisting of a solid solution of C(60)-C(70)fullerene were synthesized by a liquid-liquid interfacial precipitation method using toluene and 2-propanol as solvents.A machined crystal with a V-notch was placed in a focused ion beam scanning electron microscope where it was bent until fracture by pushing it with a molybdenum probe to measure its mechanical properties and its fracture surface was examined.The crystals had a tensile strength of 58-71 MPa,which is much higher than C60 fullerene needle-like crystals and slightly larger than alumina,and a fracture toughness of 1.1-1.3 MPa m(1/2).Moreover,it is possible to change the plasticity and fracture toughness of the C(60)-C(70)crystals by solvation of different numbers of fullerene molecules.The C(60)-C(70)fullerene crystals have the potential for use as electrodes,anchors for brittle materials,and ductile wires to carry electricity.
