Amorphous alloys with a composition(at.%)Fe_(48)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) were prepared by using either pure elements(alloy B1)or a commercial AISI430 steel as a base material(B2).When prepared from pure elements...Amorphous alloys with a composition(at.%)Fe_(48)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) were prepared by using either pure elements(alloy B1)or a commercial AISI430 steel as a base material(B2).When prepared from pure elements,alloy(B1)could be cast in plate form with a fixed thickness of 2 mm and variable lengths between 10 and 20 mm by means of copper-mold injection in an air atmosphere.In the case of alloy B2,prepared by using commercial grade raw materials,rods of 2 mm diameter are obtained.Ribbons(B1 and B2)of width 5 mm and thickness about 30μm are prepared from the arc-melted ingots using a single roller melt spinner at a wheel speed of 40 m/s.The thermal and structural properties of the samples are measured by a combination of differential scanning calorimetry(DSC),x-ray diffraction and scanning electron microscopy.Chemical compositions are checked by energy dispersive spectroscopy analysis.X-ray diffraction and scanning electron microscopy observations confirm that an amorphous structure is obtained in all the samples.A minor fraction of crystalline phases(oxides and carbides)is detected on the as-cast surface.Values of hardness and Young modulus were measured by nanoindentation for both the alloys.The effects of adverse casting conditions(such as air atmosphere,non-conventional injection copper mold casting and the partial replacement of pure elements with commercial grade raw materials)on the glass formation and properties of the alloy are discussed.展开更多
In the present work, the glass formation of Zr59Nb5Cu18Ni8Al10 (numbers indicate at %) alloy with diameter of 2 mm was prepared through water-cooled copper mold casting and in a ribbon form by the single roller melt-s...In the present work, the glass formation of Zr59Nb5Cu18Ni8Al10 (numbers indicate at %) alloy with diameter of 2 mm was prepared through water-cooled copper mold casting and in a ribbon form by the single roller melt-spinning method. This study is primarily devoted to evaluating the results obtained with the two methods of the development. The thermal stability was evaluated by differential scanning calorimetry (DSC) at a heating rate of 10℃/mn. The characteristic data of the bulk metallic glass are presented, including glass transition temperature (Tg) and crystallization temperature (Tx). The microstructure and constituent phases of the alloy composite have been analyzed by using X-ray diffraction, and observed by Scanning Electron Microscopy (SEM). The mechanical properties of bulk Zr59Nb5Cu18Ni8Al10 were alloy measured by compression tests at room temperature.展开更多
A polycrystalline dense Ti3SiC2 based ceramic material has been produced by several techniques. The effect of addition of TiC and SiC is also studied. The Ti3SiC2 material shows extraordinary electrical, thermal and m...A polycrystalline dense Ti3SiC2 based ceramic material has been produced by several techniques. The effect of addition of TiC and SiC is also studied. The Ti3SiC2 material shows extraordinary electrical, thermal and mechanical properties. Furthermore, it shows a damage tolerance capability and oxidation resistance. In this work, we have synthesized Ti3SiC2 by electro-thermal explosion chemical reaction (ETE) with high current density (900 Amperes/a.u) followed by uniaxial pressure. The structural properties of the as-prepared materials are studied by x-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX) techniques. The chemical cartography, imaging and electronic properties are investigated using Ultra-STEM and electron high energy loss resolution spectroscopy (EELS) techniques, respectively. The surface of Ti3SiC2 is characterized by means of X-ray photoelectron spectroscopy (XPS). High resolution C 1s, Si 2p, Ti 2p, Ti 3s core level spectra are explained in terms of crystallographic and electronic structure. Valence band spectrum is performed to confirm the validity of the theoretical calculations.展开更多
Fe-based bulk metallic glasses (BMGs) have been extensively studied due to their potential technological applications and their interesting physical properties such as a low modulus of elasticity, high yielding stress...Fe-based bulk metallic glasses (BMGs) have been extensively studied due to their potential technological applications and their interesting physical properties such as a low modulus of elasticity, high yielding stress and good magnetic properties. In the present work, the bulk metallic glass (BMG) formation of Fe40Ni40B20 (numbers indicate at %) with a ribbon form was fabricated by the single roller melt-spinning method. Rapid solidification leads to a fully amorphous structure for all compositions. The thermal properties associated with crystallization temperature of the glassy samples were measured using differential scanning calorimetry (DSC) at a heating rate of 10℃/mn. The microstructure and constituent phase of the alloy composite have been analyzed by using X-ray diffractometry (XRD). The effect of high temperature on the isothermal crystallization of Fe40Ni40B20 ribbon was investigated by HTX-ray diffraction. In addition, these ribbon glasses also exhibit good soft magnetic properties with M-H curvature measured under the magnetic fields between –1 kOe and 1 kOe.展开更多
基金Supported by Regione Piemonte under Grant No D23the WWS Project of the Univerity of Torino.
文摘Amorphous alloys with a composition(at.%)Fe_(48)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) were prepared by using either pure elements(alloy B1)or a commercial AISI430 steel as a base material(B2).When prepared from pure elements,alloy(B1)could be cast in plate form with a fixed thickness of 2 mm and variable lengths between 10 and 20 mm by means of copper-mold injection in an air atmosphere.In the case of alloy B2,prepared by using commercial grade raw materials,rods of 2 mm diameter are obtained.Ribbons(B1 and B2)of width 5 mm and thickness about 30μm are prepared from the arc-melted ingots using a single roller melt spinner at a wheel speed of 40 m/s.The thermal and structural properties of the samples are measured by a combination of differential scanning calorimetry(DSC),x-ray diffraction and scanning electron microscopy.Chemical compositions are checked by energy dispersive spectroscopy analysis.X-ray diffraction and scanning electron microscopy observations confirm that an amorphous structure is obtained in all the samples.A minor fraction of crystalline phases(oxides and carbides)is detected on the as-cast surface.Values of hardness and Young modulus were measured by nanoindentation for both the alloys.The effects of adverse casting conditions(such as air atmosphere,non-conventional injection copper mold casting and the partial replacement of pure elements with commercial grade raw materials)on the glass formation and properties of the alloy are discussed.
文摘In the present work, the glass formation of Zr59Nb5Cu18Ni8Al10 (numbers indicate at %) alloy with diameter of 2 mm was prepared through water-cooled copper mold casting and in a ribbon form by the single roller melt-spinning method. This study is primarily devoted to evaluating the results obtained with the two methods of the development. The thermal stability was evaluated by differential scanning calorimetry (DSC) at a heating rate of 10℃/mn. The characteristic data of the bulk metallic glass are presented, including glass transition temperature (Tg) and crystallization temperature (Tx). The microstructure and constituent phases of the alloy composite have been analyzed by using X-ray diffraction, and observed by Scanning Electron Microscopy (SEM). The mechanical properties of bulk Zr59Nb5Cu18Ni8Al10 were alloy measured by compression tests at room temperature.
文摘A polycrystalline dense Ti3SiC2 based ceramic material has been produced by several techniques. The effect of addition of TiC and SiC is also studied. The Ti3SiC2 material shows extraordinary electrical, thermal and mechanical properties. Furthermore, it shows a damage tolerance capability and oxidation resistance. In this work, we have synthesized Ti3SiC2 by electro-thermal explosion chemical reaction (ETE) with high current density (900 Amperes/a.u) followed by uniaxial pressure. The structural properties of the as-prepared materials are studied by x-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX) techniques. The chemical cartography, imaging and electronic properties are investigated using Ultra-STEM and electron high energy loss resolution spectroscopy (EELS) techniques, respectively. The surface of Ti3SiC2 is characterized by means of X-ray photoelectron spectroscopy (XPS). High resolution C 1s, Si 2p, Ti 2p, Ti 3s core level spectra are explained in terms of crystallographic and electronic structure. Valence band spectrum is performed to confirm the validity of the theoretical calculations.
文摘Fe-based bulk metallic glasses (BMGs) have been extensively studied due to their potential technological applications and their interesting physical properties such as a low modulus of elasticity, high yielding stress and good magnetic properties. In the present work, the bulk metallic glass (BMG) formation of Fe40Ni40B20 (numbers indicate at %) with a ribbon form was fabricated by the single roller melt-spinning method. Rapid solidification leads to a fully amorphous structure for all compositions. The thermal properties associated with crystallization temperature of the glassy samples were measured using differential scanning calorimetry (DSC) at a heating rate of 10℃/mn. The microstructure and constituent phase of the alloy composite have been analyzed by using X-ray diffractometry (XRD). The effect of high temperature on the isothermal crystallization of Fe40Ni40B20 ribbon was investigated by HTX-ray diffraction. In addition, these ribbon glasses also exhibit good soft magnetic properties with M-H curvature measured under the magnetic fields between –1 kOe and 1 kOe.
