| The bulk amorphous alloys with the high strength, high hardness, strong corrosion resistance and outstanding mechanical properties have extensive application prospect but its structure research is still a problem. Because the acoustical parameters such as ultrasound velocity and n attenuation can reveal the material properties and information about the inside microstructure well when the ultrasound spread in medium, the ultrasound performance and elastic properties can provide the information about the microstructure. However, the research of the bulk amorphous and the experimental ultrasonic and elastic data in the present are limited. At the same time the study of Zr-based amorphous alloys has been in the domain forefront in massive amorphous and many important research results and theory of bulk amorphous alloy are first founded in Zr-based amorphous alloys. Therefore, the study of Zr-based amorphous alloy systems plays an important role in guiding the study of other amorphous alloy system.A series of ZrAINi ternary bulk metallic glasses (BMGs) with the diameter of 4mm were prepared by the copper mould suction casting method. The structure of the BMGs was analyzed by using the X-ray diffraction and Metallographic analysis. The thermal parameters were obtained by Differential thermal analysis and Differential scanning calorimeter. According to the Archimedes principle, the measurement of the density was carried out by the electronic balance. Based on the longitudinal wave grazing incidence principle, the ultrasonic velocities were measured by the ultrasonic water-immersion focusing ways and the elastic constants were obtained by the formulas. Using the micro hardness tester and compression test enginery measured the micro hardness and compression fracture strength of the amorphous alloy.Combined with thermal analysis parameters, we studied the change of the ultrasonic properties of [Ni3Zr8]Alx (x=1,1.5,2,3) which had the same clusters and the different connected Al content. The results showed that the longitudinal (Vl) and transverse velocity (Vt) had the same increased trends as Tg, while the density show the opposite when the x increased. The possible reasons for this were that the increased connected atomic Al result in the stronger bonding force increasing among the atoms. When x increased from 1 to 3 the elastic modulus E and G increased 27.2% and 25.1% respectively while Poisson's ratioγ decreased 5.2%. It was shown that elastic modulus were very sensitive to the component change. In addition, young's modulus E and Tg/Tm which can represent the GFA of the BMGS exhibited the same trend with consistent, and the results showed E and GFA had some particular concern in this work.The ultrasound method was used to study the difference on the elastic modulus among the four series of ZrAlNi BMGs which the ratio of the clusters and Al contents was 1:x (x=1,1.5,2.3) called Al] Al1.5, Al2 and Al3. Combined with thermal analysis, micro hardness and compression fracture strength, the correlations between the elastic properties and heat stability and mechanical properties were researched. Results show that the velocity and elastic modulus variation trend was Al3>Al2>Al1.5>Al1 but the Poisson's ratio and B/G showed the contrary trend. Compared with Tg, Tx, the linear relationship between E, G and Tg/p, Tx/p were more obvious. While the linear relation between the body modulus B and Tg, Tx were not obvious. The decreased relationship which could be expressed as B/G=10.6-10.86Tg/Tm between B/G and Tg/Tm might indicate that the B/G ratio could also available to judge the GFA of BMGs preliminary. E and microhardness HV and compression fracture strength a all showed to increasing trend, which could play a certain directive role in designing novel amorphous with good thermal stability and mechanical properties. |
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