Thermokinetics driven microstructural evolution during laser-based additive manufacturing of γ-TiAl alloy

IF 4.8 2区材料科学 Q2 CHEMISTRY, PHYSICAL

Intermetallics Pub Date : 2025-09-09 DOI:10.1016/j.intermet.2025.108984

K.N. Chaithanya Kumar , Madhavan Radhakrishnan , Zane Weldon Hughes , Selvamurugan Palaniappan , Shashank Sharma , Rajarshi Banerjee , Satyam Suwas , Narendra B. Dahotre

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引用次数: 0

Abstract

This work investigates effects of thermokinetics on evolution of microstructure in additively manufactured Ti4822 alloy fabricated with identical processing parameters under intrinsically different thermokinetic conditions associated with heights of 4 mm and 10 mm with a same base cross-sectional area. Despite similar printing conditions, distinctly different microstructures were observed due the different thermokinetics experienced by each one of them. While 4 mm component possessed a fine scale lamellar γ+α₂ microstructure, the 10 mm component generated coarsened γ grains with spheroidized α₂ pockets. A component-scale thermal model was employed to explain the thermokinetics driven phase transformations. The difference in microstructure is attributed to thermal histories experienced during fabrication by components of different volumes. Specifically, rapid cooling from above the α-transus temperature promoted fine γ-lath formation in the 4 mm component, whereas slower cooling through the γ+α phase field in the 10 mm component resulted in coarsened γ grains. The nanoindentation based hardness and elastic modulus correlates well with the microstructural changes observed in the fabricated components. These findings offer valuable insights into tailoring microstructures by exploiting the novel thermokinetics intrinsic to additive manufacturing processes.

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激光增材制造γ-TiAl合金过程中热动力学驱动的显微组织演变

本文研究了相同工艺参数下增材制造Ti4822合金在相同基底横截面积下4 mm和10 mm两种不同热动力学条件下微观组织演变的热力学影响。尽管打印条件相似，但由于每一种材料所经历的热动力学不同，因此观察到明显不同的微观结构。4mm组分具有细小的层状γ+α2微观结构，而10mm组分具有粗化的γ晶粒和球化的α2口袋。采用组分尺度热模型来解释热动力学驱动的相变。微观结构的差异归因于不同体积的组件在制造过程中经历的热历史。具体来说，在α-横截面温度以上的快速冷却促进了4mm组分中细小γ-板条的形成，而在10mm组分中通过γ+α相场的缓慢冷却导致了γ晶粒的粗化。纳米压痕硬度和弹性模量与材料的显微组织变化密切相关。这些发现为利用增材制造过程中固有的新型热力学来定制微结构提供了有价值的见解。

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

Intermetallics 工程技术-材料科学：综合

CiteScore

7.80

自引率

9.10%

发文量

291

审稿时长

37 days

期刊介绍： This journal is a platform for publishing innovative research and overviews for advancing our understanding of the structure, property, and functionality of complex metallic alloys, including intermetallics, metallic glasses, and high entropy alloys. The journal reports the science and engineering of metallic materials in the following aspects: Theories and experiments which address the relationship between property and structure in all length scales. Physical modeling and numerical simulations which provide a comprehensive understanding of experimental observations. Stimulated methodologies to characterize the structure and chemistry of materials that correlate the properties. Technological applications resulting from the understanding of property-structure relationship in materials. Novel and cutting-edge results warranting rapid communication. The journal also publishes special issues on selected topics and overviews by invitation only.