Quantitative analysis on microstructure characteristic of pre-strained β-solidified TiAl alloy during post-heat treatment

IF 3.8 2区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

Vacuum Pub Date : 2024-09-18 DOI:10.1016/j.vacuum.2024.113662

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Abstract

The β/βo phase in β-solidified TiAl alloys plays a contradictory role in improving processability at high temperatures but deteriorating performance at service temperature due to its ordering transformation. After exerting its positive role during thermomechanical processing, it must be eliminated or reduced to a minimum through post-heat treatment. In this study, the microstructural evolution of the pre-strained Ti-43.24Al-8.42Nb-0.20W-0.21B-0.24Y alloy on post-heat treatment is investigated, and a quantitative relationship between β_o phase content and the pre-strain is established. Due to the difference in driving force of phase transformation, with decreasing pre-strain the microstructure displays varied characteristics from a mixed structure comprising (α₂+γ) lamellar colonies, γ blocks, and βo phase, to a nearly-lamellar structure after post-heat treatment at 1270 °C/4h/FC. Only if the pre-strain is less than 0.78, a refined nearly-lamellar structure can be achieved. This work provides important theoretical guidance for practical forging processing of β-solidified TiAl alloys.

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后热处理过程中预应力 β 固化 TiAl 合金微观结构特征的定量分析

β固结钛铝合金中的β/βo相在高温下改善加工性能，但在使用温度下却因其有序转变而降低性能，这种矛盾的作用。在热机械加工过程中发挥积极作用后，必须通过后热处理将其消除或减少到最低程度。本研究研究了预应变 Ti-43.24Al-8.42Nb-0.20W-0.21B-0.24Y 合金在后热处理过程中的微观结构演变，并建立了 βo 相含量与预应变之间的定量关系。由于相变的驱动力不同，随着预应变的减小，微观结构表现出不同的特征，从由 (α2+γ) 层状菌落、γ 块和 βo 相组成的混合结构，到在 1270 °C/4h/FC 下进行后热处理后的近似层状结构。只有当预应变小于 0.78 时，才能获得精细的近似层状结构。这项研究为β固化TiAl合金的实际锻造加工提供了重要的理论指导。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Vacuum 工程技术-材料科学：综合

CiteScore

6.80

自引率

17.50%

发文量

审稿时长

34 days

期刊介绍： Vacuum is an international rapid publications journal with a focus on short communication. All papers are peer-reviewed, with the review process for short communication geared towards very fast turnaround times. The journal also published full research papers, thematic issues and selected papers from leading conferences. A report in Vacuum should represent a major advance in an area that involves a controlled environment at pressures of one atmosphere or below. The scope of the journal includes: 1. Vacuum; original developments in vacuum pumping and instrumentation, vacuum measurement, vacuum gas dynamics, gas-surface interactions, surface treatment for UHV applications and low outgassing, vacuum melting, sintering, and vacuum metrology. Technology and solutions for large-scale facilities (e.g., particle accelerators and fusion devices). New instrumentation ( e.g., detectors and electron microscopes). 2. Plasma science; advances in PVD, CVD, plasma-assisted CVD, ion sources, deposition processes and analysis. 3. Surface science; surface engineering, surface chemistry, surface analysis, crystal growth, ion-surface interactions and etching, nanometer-scale processing, surface modification. 4. Materials science; novel functional or structural materials. Metals, ceramics, and polymers. Experiments, simulations, and modelling for understanding structure-property relationships. Thin films and coatings. Nanostructures and ion implantation.