张健,张熹雯,刘瑞平,等.微量B元素对铸造Ti2AlNb合金组织与力学性能的影响[J].精密成形工程,2022,14(11):210-217.
ZHANG Jian,ZHANG Xi-wen,LIU Rui-ping,et al.Effect of Trace B on Microstructure and Mechanical Properties of Cast Ti2AlNb Alloy[J].Journal of Netshape Forming Engineering,2022,14(11):210-217. |
| 微量B元素对铸造Ti2AlNb合金组织与力学性能的影响 |
| Effect of Trace B on Microstructure and Mechanical Properties of Cast Ti2AlNb Alloy |
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| DOI：10.3969/j.issn.1674-6457.2022.11.020 |
| 中文关键词: 铸造Ti2AlNb合金 微观组织 力学性能 硼化物 |
| 英文关键词: cast Ti2AlNb alloy microstructure mechanical properties borides |
| 基金项目:国家科技重大专项(J2019–VI–0003–0116) |
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| 中文摘要: |
| 目的 研究微量B元素对铸造Ti2AlNb合金组织和力学性能的影响，优选出适合铸造工艺的Ti2AlNb合金成分，为推进铸造Ti2AlNb合金的应用提供理论和数据支撑。方法 以Ti–22Al–25Nb(原子数分数，下同)、Ti–22Al–24Nb–0.1B、Ti–22Al–24Nb–0.2B合金为研究对象，采用光学显微镜、扫描电镜研究不同B含量合金铸态、热等静压态的宏、微观组织及析出相形态。采用XRD分析合金的物相组成，室温拉伸性能测试评价力学性能，通过扫描电镜观察拉伸断口，分析微量B元素对力学性能产生影响的原因。结果 添加微量B元素可以明显细化Ti–22Al–25Nb合金的晶粒尺寸，随着B元素原子数分数增加至0.2%，晶粒尺寸由958 μm减小至548 μm。B元素在合金中主要以固溶态、TiB和TiB2针片状析出相形式存在，随着B含量的增加，硼化物长度和厚度尺寸略微增加、体积分数由0.3%增加至0.8%。0.1B合金的室温屈服强度、抗拉强度和伸长率与原合金水平相当，0.2B合金的屈服强度提升，但其抗拉强度和伸长率均降低。断口分析显示，0.2B合金塑性降低是硼化物增多、集中分布引起脆性断裂所致。结论 综合B元素对流动性的改善效果，优选出适合铸造工艺的合金成分为Ti–22Al–24Nb–0.1B。 |
| 英文摘要: |
| The work aims to study the effect of trace B element on the microstructure and mechanical properties of cast Ti2AlNb alloy, and to optimize the composition of Ti2AlNb alloy suitable for casting process, so as to provide theoretical and data support for promoting the application of cast Ti2AlNb alloy. The Ti-22Al-25Nb (at.%, the same below), Ti-22Al-24Nb-0.1B and Ti-22Al-24Nb-0.2B alloys were used as the research objects, optical microscopy and scanning electron microscopy were used to study the macrostructure, microstructure and precipitate morphology of the as-cast and hot isostatic alloy with different B content. The phase composition of the alloy was analyzed by XRD, and the mechanical properties were evaluated by the tensile property test at room temperature. The tensile fractures were observed by scanning electron microscope, and the reasons for the influence of trace B element on the mechanical properties were analyzed. The results show that the addition of trace element B can obviously refine the grain size of Ti-22Al-25Nb alloy. With the increase of element B content to 0.2at.%, the grain size decreases from 958 μm to 548 μm. Element B mainly exists in the form of solid solution, needle precipitated phase of TiB and TiB2 in the alloy. With the increase of B content, the length and thickness of boride increase slightly, and the volume fraction increases from 0.3% to 0.8%. The yield strength, tensile strength and elongation of 0.1B alloy at room temperature are similar to those of the original alloy. The yield strength of 0.2B alloy increases, but the tensile strength and elongation decrease. Fracture analysis shows that the decrease of the plasticity of 0.2B alloy is due to the brittle fracture caused by the increase of boride and its concentrated distribution. The alloy composition suitable for casting process is Ti-22Al-24Nb-0.1B based on the improving effect of element B on fluidity. |
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