【作者】 夏明星；

【导师】 胡锐；

【作者基本信息】 西北工业大学 ， 材料加工工程， 2007， 硕士

【摘要】 非晶合金由于具有许多不同于传统晶态材料的优异性能而成为材料研究领域的热点之一，而对于近年来发展的Ti基非晶的研究还不够深入。本文采用电弧熔炼、感应熔炼、喷铸、吸铸及单辊旋淬的方法分别制备了块体合金和薄带样品。利用XRD、SEM、OM、TEM、DSC、万能试验机及维氏硬度机等实验手段，比较系统地研究了W、SiC、Al、B对Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈非晶合金的结构、热稳定性、力学性能的影响。本文研究的主要内容和获得的结论如下： 采用喷铸法制备Φ3mm的Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈非晶合金，其过冷液相区宽度ΔT_x为45K，有较好的热稳定性，其抗压强度σ_bc、塑性应变ε_pc分别为1963MPa和3.9％。 探讨了添加W对Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈非晶合金的影响。对薄带而言，W的添加不改变合金的非晶态结构；而对于Φ3mm试样，其结构为非晶相、Ti_xW_1-x、CuTi、NiTi₂晶体相，同时材料的抗压强度大幅度下降，硬度略有增加。 考察了SiC对Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈非晶合金的影响。对薄带而言，由于SiC与合金发生剧烈的反应，形成了TiC颗粒+非晶的复相结构，TiC颗粒抑制或延缓了非晶合金中准晶相的析出，从而提高材料的热稳定性：对于Φ3mm试样则形成非晶、TiC、硅化物的复合结构，由于硬质相TiC的存在合金的硬度随之增加。 较系统的研究了Al对Φ3mm Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈非晶合金试样的影响。结果表明，替代和掺杂5at％Al分别析出纳米晶和准晶，提高了非晶合金的T_g和ΔT_x，热稳定性加强；对于力学性能而言，以替代方式添加抗压强度提高到2121MPa，塑性应变降为0.2％，以掺杂方式添加后合金具有零塑性，强度降低为1475 MPa。 最后，分析了B对Φ3mmTi₄₀Zr₂₅Ni₈Cu₉Be₁₈非晶合金的影响。当B含量低于2％时，合金的结构都为单一非晶态结构，在B含量为3％时，合金为非晶态+CuTi、NiTi₂、TiB晶体相的复合结构。随着B含量的增加，强度和硬度值均呈现先增加后下降的趋势，其中当B含量为1％时，抗压强度σ_bc可达2139MPa。更多还原

【Abstract】 Recently, metallic glass alloys, especially, Ti-based metallic glass alloys, are focused in material science field due to their excellent properties that are different from traditional metal materials. In this paper, bulk and ribbon sample were prepared by arc melting, inducing melting, injecting casting, sucking casting and melt-spun methods. The effect of W, SiC, Al, B on the microstructure, thermal stability and mechanical properties of Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈ metallic glass were investigated by XRD, SEM, OM, TEM, DSC, mechanical testing machine and Vickers microhardness machine. The main conclusions are as follows:The Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈ amorphous alloy with a diameter of 3mm was prepared by injection casting method. Its supercooled liquid region （ΔT_x） is 45K. It means that the alloy has good thermal stability. Its compression strength σ_bc and plastic strain ε_pc are 1963MPa and 3.9%, respectively.The effect of W on Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈ metallic glass was investigated. The addition of W isn’t able to change the amorphous structure of ribbon sample. But Ti_xW_1-x, CuTi and NiTi₂ crystal phases are distributed in the amorphous matrix when the size of sample is up to Φ3mm. At the same time, compression strength of alloy decreases dramatically and the hardness slightly increases.The property of Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈ metallic glass could also be affected dramatically by low content of SiC. SiC reacts with the alloy melt dramatically. TiC and amorphous phase appear in the microstructure of ribbon sample. TiC Particulate can block or delay the precipitation of quasicrystalline phase of metallic alloy. It results in better thermal stability. The structure of Φ3mm sample are composed of TiC, silicides and amorphous. The hardness of alloy increases because of the horniness phase TiC.The effect of Al on Ti₄₀Zr₂₅Ni₈Cu₉Be₁₈ metallic glass with Φ3mm was investigated in this paper. The result shows that different volume fraction of nanocrystalline and quasicrystalline are obtained with the 5at% Al addition. The addition of Al improves T_g of the amorphous alloy and increases the supercooled liquid region ΔT_x of the amorphous alloy. It means the enhancement of the thermal更多还原