Structure And Properties Of Zr-Based Bulk Metallic Glasses After Ultrasonic Treatment

The Structure and properties of Zr-based bulk metallic glasses before and after ultrasonic treatment have been investigated.Zr₅₀Cu₅₀ and Zr₅₅Al₁₀Ni₅Cu₃₀ bulk metallic glasses (BMG) have been prepared by the copper mold casting method, and treated by ultrasonic technology.The changes of the specific heat (Cp) for Zr₅₀Cu₅₀ and Zr₅₅Al₁₀Ni₅Cu₃₀ BMG before and after ultrasonic treatment were analyzed by the differential scanning calorimetry (DSC). The results indicate that the specific heat (Cp),the crystallization enthalpy and the fusion enthalpy of the two bulk metallic glasses become bigger after ultrasonic treatment.The crystallization kinetics of Zr₅₅Al₁₀Ni₅Cu₃₀ BMG was investigated by DSC before and after ultrasonic treatment. The results indicate that the crystallization process of Zr₅₅Al₁₀Ni₅Cu₃₀ BMG can be regarded as a kinetic process basing on the heating rate. The crystallization activation energy of Zr₅₅Al₁₀Ni₅Cu₃₀ bulk metallic glasses was calculated by the Kissinger′s equation. The results show that the Zr₅₅Al₁₀Ni₅Cu₃₀ BMG has the higher crystallization activation energy and the higher thermal stability after ultrasonic treatment.The mechanical property of Zr₅₅Al₁₀Ni₅Cu₃₀ BMG before and after ultrasonic treatment was studied by nanoindentor. The results indicate that the distribution of the reduced nanoindentation hardness for Zr₅₅Al₁₀Ni₅Cu₃₀ BMG after ultrasonic treatment was more wider by comparing the untreated sample, the nanohardness and elastic modulus of Zr₅₅Al₁₀Ni₅Cu₃₀ BMG after ultrasonic treatment are higher by comparing the untreated sample. The change of the excess free volume for Zr₅₅Al₁₀Ni₅Cu₃₀ BMG before and after ultrasonic treatment was researched by using the high pressure energy dispersive X-ray diffraction. It is found that the structure of Zr₅₅Al₁₀Ni₅Cu₃₀ amorphous alloy before and after ultrasonic treatment was stable under the testing pressure (the sample before ultrasonic treatment increased the pressure from 0 to 31.19 GPa and the sample after ultrasonic treatment increased the pressure from 0 to 30.40 GPa). The equations of state of the bulk metallic glasses before and after ultrasonic treatment were determinated. The Bulk modulus of Zr₅₅Al₁₀Ni₅Cu₃₀ BMG after ultrasonic treatment is bigger by comparing the untreated sample.