Compositional dependence of thermal and elastic properties of Cu-Ti-Zr-Ni bulk metallic glasses

摘要

Starting from the quaternary Cu47Ti34Zr11Ni8 alloy,the compositional dependence of thermal and elastic properties of Cu-Ti-Zr-Ni alloys was systematically investigated.Quaternary Cu-Ti-Zr-Ni alloys can be cast directly from the melt into copper molds to form fully amorphous strips or rods with the thickness of 3-6 mm.The evidence of the amorphous nature of the cast rods was provided by X-ray spectra.The measured glass transition temperature(Tg) and crystallization temperature(Tx) were obtained for the alloys using differential scanning calorimetry(DSC) at the heating rate of 20 K/s.In the results,the differences between the glass temperature and the crystallization temperature(ΔTx=Tx-Tg) are measured with values ranging up to 33-55 K.The reduced glass transition temperature(Trg),which is the ratio of the glass temperature to the liquidus temperature(Tl),is often used as an indication of the glass-forming ability of metallic alloys.For the present Cu-Ti-Zr-Ni alloys,this ratio is typically in the range of 0.5838-0.5959,characteristic of metallic alloys with good glass-forming ability.The elastic constants for several selected alloys were measured using ultrasonic methods.The values of the elastic shear modulus,bulk modulus,and Poisson's ratio were also given.