Synthesis And Properties Ti-Zr-Be-Co Bulk Metallic Glasses

Ti-based bulk metallic alloys have attracted the attention of many researchers because of their low density,high strength,high elastic limit and good corrosion resistance.They have good engineering applications in biomedical,aerospace,and marine engineering.prospect.The existing Ti bulk metallic alloy has the disadvantages of weak glass forming ability and poor plasticity,and limits the industrial application of Ti metallic alloy.Therefore,the development of a Ti-based amorphous alloy with high strength and high elastic limit,as well as strong glass forming ability and excellent plasticity,has great practical significance.In this paper,we aim to develop a new Ti-based bulk metallic s alloy with engineering application prospects,strong glass forming ability and large plasticity,and study on the ternary Ti-Zr-Be alloy system with strong glass forming ability.Starting point,Ti₄₅Zr₂₀Be₃₅is selected as the master alloy,and the micro-alloying method is realized by adding Co element to explore and develop a new Ti-based amorphous alloy.A total of 16 different alloys of the Ti-Zr-Be-Co alloy system were prepared by a copper mold cooling and suction casting method.By characterizing its performance by means of XRD,DSC and other equipment,we found that the addition of Co element effectively improved the glass forming ability and plasticity of Ti₄₅Zr₂₀Be₃₅ amorphous alloy.Studies have shown that in addition to the alloy 15 alloys other than the parent alloy Ti₄₅Zr₂₀Be₃₅,the alloy with 13 components has an increased glass forming ability compared to the parent alloy.When the Co content is12 at.%,the critical dimension of Ti₄₅Zr₂₀Be₂₃Co₁₂2 metallic alloy is 15mm,and when the Co content is 10 at.%,the plastic strain of Ti₄₅Zr₂₀Be₂₅Co₁₀0 amorphous alloy is 15.7%,and the breaking strength can reach 2465Mpa.In order to continue to explore the relationship between amorphous glass forming ability and plasticity and crystallization activation energy,we conducted experiments on four alloys of Ti₄₅Zr₂₀Be₃₅,Ti₄₅Zr₂₀Be₃₁Co₄,Ti₄₅Zr₁₆Be₂₃Co₄,and(Ti₄₅Zr₂₀Be₃₅)Co_4.In order to further study the thermoplastic forming ability of Ti-based bulk metallic alloys,we used static thermomechanical analysis?TMA?to test the different alloys obtained,and used thermodynamics such as supercooled liquid region width and normalized parameter S.The parameters are analyzed.The results of the analysis indicate that alloys having a large supercooled liquid region width and a large S value generally have a strong thermoplastic forming ability.The best thermoplastic forming ability is Ti₄₅Zr₂₀Be₂₇Co₈alloy,which has a Co content of 8 at.%and a deformation amount of 205?m in the supercooled liquid region.At the same time,the alloy also has a large supercooled liquid region and S.parameter.It is indicated that the supercooled liquid phase and the S-parameter can be used as important criteria for measuring the thermoplastic forming ability of Ti metallic alloy.The difficulty of crystallization of amorphous alloys has an important effect on the glass forming ability and plasticity of glass metallic alloys.Studying the crystallization behavior of metallic alloys helps us to control the microstructure changes of metallic alloys during crystallization.And material properties,the activation energy of Ti45Zr20Be35,Ti45Zr20Be31Co4,Ti45Zr16Be23Co4,and?Ti45Zr20Be35?Co4 alloy calculated using Kisssinger and Ozawa equations.Activation energy is an important kinetic parameter for measuring the difficulty of crystallization of metallic alloys.By comparing the activation energy,we find that alloys with better glass forming ability often have larger crystallization activation energy.Then we carried out electrochemical corrosion research on the alloy,trying to select a Ti-based bulk metallic alloy which not only has high strength,high glass forming ability and other excellent properties,but also has excellent corrosion resistance.The results show that the self-corrosion potential of Ti₄₅Zr₂₀Be₃₁Co₄,Ti₄₅Zr₁₆Be₂₃Co₄,and(Ti₄₅Zr₂₀Be₃₅)Co₄alloys with Co element is improved compared with 1.157x10^-6A/cm3 of the parent alloy Ti₄₅Zr₂₀Be₃₅.indicating that the addition of Co element is beneficial to improve the corrosion resistance of the alloy.