The bulk Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1, 3, 5, 7, 9） amorphous rods with diameters of 1.5 mm were successfully prepared by copper mold casting method with the low purity raw materials....The bulk Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1, 3, 5, 7, 9） amorphous rods with diameters of 1.5 mm were successfully prepared by copper mold casting method with the low purity raw materials. The amorphous and crystalline states, and thermal parameters, such as the glass transition temperature （Tg）, the initial crystallization temperature （Tx）, the supercooled liquid region （ΔTx=Tx-Tg）, the reduced glass transition temperature T<sup>rg （Tg/Tm, Tm: the onset temperature of melting of the alloy, and Tg/Tl, Tl: the finished temperature of melting of the alloy） were investigated by X-ray diffractometry （XRD） and differential scanning calorimetry （DSC） analysis. Glass forming ability of Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1,3,5,7,9） bulk metallic glasses has been studied. According to the results, the alloy （x=7） with the highest T<sup>rg （Tg/Tl=0.607, Tg/Tl=0.590） value, has the strongest glass forming ability among these alloys because its composition is near eutectic composition. The wide supercooled liquid region over 72 K indicates the high thermal stability for this alloy system. This bulk metallic glass exhibits quite high strength （Hv 1020）. The success of production of the Fe-based bulk metallic glass with industrial materials is of great significance for the future progress of basic research and practical application.展开更多
Cu46Zr46A14.8Ti3.2 bulk metallic glass （BMG） was successfully synthesized by copper-mold casting and the mechanical properties at room temperature were measured by compression tests. The structure and thermal charac...Cu46Zr46A14.8Ti3.2 bulk metallic glass （BMG） was successfully synthesized by copper-mold casting and the mechanical properties at room temperature were measured by compression tests. The structure and thermal characteristics were analyzed by XRD and DSC, and the fracture surface morphology was examined by SEM. The glassy alloy with 4 mm in diameter shows an high fracture strength of 1 960 MPa, with an improvement of about 20% compared to the ultimate compression fracture strength of the Cu46Zr46A18 BMG, which suggests that the Ti addition improves the compression fracture strength. The different degrees of the adiabatic heating induce four types of fracture features： a vein-like structure, an elongated and striated vein pattern, melting and smooth regions. The elongated and striated vein patterns as well as the melting region show that enormous strain energy is released, which causes significant adiabatic heating. Furthernaore, many micro-cracks observed in the smooth region are caused by the strong shear force. In addition, the strong shear force leads to many shear bands as well as the melting in the lateral surface.展开更多
文摘The bulk Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1, 3, 5, 7, 9） amorphous rods with diameters of 1.5 mm were successfully prepared by copper mold casting method with the low purity raw materials. The amorphous and crystalline states, and thermal parameters, such as the glass transition temperature （Tg）, the initial crystallization temperature （Tx）, the supercooled liquid region （ΔTx=Tx-Tg）, the reduced glass transition temperature T<sup>rg （Tg/Tm, Tm: the onset temperature of melting of the alloy, and Tg/Tl, Tl: the finished temperature of melting of the alloy） were investigated by X-ray diffractometry （XRD） and differential scanning calorimetry （DSC） analysis. Glass forming ability of Fe<sup>60 CoxZr<sup>10 Mo5W2B<sup>23-x （x=1,3,5,7,9） bulk metallic glasses has been studied. According to the results, the alloy （x=7） with the highest T<sup>rg （Tg/Tl=0.607, Tg/Tl=0.590） value, has the strongest glass forming ability among these alloys because its composition is near eutectic composition. The wide supercooled liquid region over 72 K indicates the high thermal stability for this alloy system. This bulk metallic glass exhibits quite high strength （Hv 1020）. The success of production of the Fe-based bulk metallic glass with industrial materials is of great significance for the future progress of basic research and practical application.
基金Project(NCET-10-0360) supported by the Program for New Century Excellent Talents in University,ChinaProject supported by the Fundamental Research Funds for the Central Universities,China
文摘Cu46Zr46A14.8Ti3.2 bulk metallic glass （BMG） was successfully synthesized by copper-mold casting and the mechanical properties at room temperature were measured by compression tests. The structure and thermal characteristics were analyzed by XRD and DSC, and the fracture surface morphology was examined by SEM. The glassy alloy with 4 mm in diameter shows an high fracture strength of 1 960 MPa, with an improvement of about 20% compared to the ultimate compression fracture strength of the Cu46Zr46A18 BMG, which suggests that the Ti addition improves the compression fracture strength. The different degrees of the adiabatic heating induce four types of fracture features： a vein-like structure, an elongated and striated vein pattern, melting and smooth regions. The elongated and striated vein patterns as well as the melting region show that enormous strain energy is released, which causes significant adiabatic heating. Furthernaore, many micro-cracks observed in the smooth region are caused by the strong shear force. In addition, the strong shear force leads to many shear bands as well as the melting in the lateral surface.
