Ti-Cu-Ni-Zr大块非晶合金玻璃形成能力与力学性能

Glass Forming Ability of Ti-Cu-Ni-Zr Bulk Metallic Glass and Its Mechanical Properties

采用"二元共晶混合"法设计富Ti基Ti-Cu-Ni-Zr合金成分,通过水冷铜模铸造法制备出不同直径Ti-Cu-Ni-Zr合金棒材。利用X射线衍射仪(XRD)、差示扫描量热仪(DSC)、万能试验机和扫描电镜(SEM)研究合金的玻璃形成能力和力学性能。结果表明,Ti-Cu-Ni-Zr合金具有较高玻璃形成能力,其中Ti_(38)Cu_(45.26)Ni_(9.14)Zr_(7.6)合金最大临界直径为3 mm;Ti-Cu-Ni-Zr合金玻璃形成能力与Trg值关系较大,而与ΔTx、γ值关系较小。通过对合金力学性能进行研究,结果表明,Ti_(38)Cu_(45.26)Ni_(9.14)Zr_(7.6)非晶合金具有屈服强度1 937 MPa,断裂强度2 071 MPa,且具有0.6%的塑性,而Ti_(39)Cu_(43.8)Ni_(9.6)Zr_(7.6)非晶合金断裂机制为完全脆性断裂;对于完全脆性断裂的Ti_(39)Cu_(43.8)Ni_(9.6)Zr_(7.6)非晶合金,主剪切面和次剪切带可能同时发生。

The compositions of the rich Ti-based Cu-Ti-Ni-Zr alloys were designed by using the ＂binary eutectic mixture＂ method, and the Ti-Cu-Ni-Zr alloy rods with the different diameters were prepared using water-cooled copper mold casting. The glass forming ability and mechanical properties of the alloys were studied by means of X-ray diffraction （XRD）, differential scanning calorimetry （DSC）, universal testing machine and scanning electron microscope （SEM）. The results show that the Ti38Cu45.26Ni9.14Zr7.6 alloy with the diameter of 3 rnm has the higher glass forming ability. In addition, its reduced glass transition temperature Trg value is smaller than that of the Cu51.1Ti34.1Ni7.2Zr7.6 alloy with the critical diameter of 3 mm. The relationship between the glass forming ability in Ti-Cu-Ni-Zr alloys and the Trg values are stronger than the ATx and γ values. The mechanical properties of the alloys were studied. The results show that the Ti38Cths.2e, Nig.14ZrT.6 alloy has the yield strength of 1 937 MPa, the crack strength of 2 071 MPa, and the plastic of 0.6%, respectively; however, the fracture mechanism of Ti39Cu43.8Ni9.6Zr7.6 alloy is completely brittle fracture. For the Ti39Cu43.8Ni9.6Zr7.6 metallic glass, the primary shear and secondary shear bands may occur simultaneously.