Yarong Wang, Yuqing Li, Yonghao Yu, Hongchao Kou, Jinshan Li
{"title":"Micro-structural damage and mechanical response of TiAl alloy with lamellar microstructure during thermal shock progress","authors":"Yarong Wang, Yuqing Li, Yonghao Yu, Hongchao Kou, Jinshan Li","doi":"10.1016/j.intermet.2024.108280","DOIUrl":null,"url":null,"abstract":"<div><p>Considering the service safety for TiAl alloy under thermal shock, the effect of thermal shock temperature and cycles on micro-structural degeneration and mechanical properties were studied. The results show that the vertical decomposition of α<sub>2</sub>→β<sub>0</sub> phase transition occurs in α<sub>2</sub> lamellae if the single thermal shock temperature increases to 1000 °C or the thermal shock cycle increases to 10 times at 900 °C. Cracks form during the thermal shock progress as the single thermal shock temperature increases to 1000 °C or the number of thermal shocks is 5 times at 900 °C. Simultaneously, the flexural strength of samples decreases to 70% of the initial flexural strength under the same condition. It indicates that Ti–45Al–4Nb–1Mo-0.1B alloy fails as the single thermal shock temperature is above 1000 °C or the number of thermal shocks exceeds 5 times at 900 °C, and cracks generated during the thermal shock progress cause the dramatic deterioration in flexural strength. Meanwhile, the formed cracks are coarse, and the propagation path is relatively straight, which further deteriorates the flexural strength of the Ti–45Al–4Nb–1Mo-0.1B alloy. Besides, the nucleation and propagation of cracks change with the thermal shock temperature and cycles were analyzed. When the single thermal shock temperature is 1000 °C, the nucleation of cracks is not only in lamellar colony boundaries but also in α<sub>2</sub>/γ lamellar interfaces and the propagation path of cracks is relatively straight compared with the formation of cracks after 5 thermal shocks at 900 °C, because the thermal stress increases, and then cracks directly pass through lamellar colonies when the angle between lamellar orientation and crack propagation direction is about 90°.</p></div>","PeriodicalId":331,"journal":{"name":"Intermetallics","volume":null,"pages":null},"PeriodicalIF":4.3000,"publicationDate":"2024-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Intermetallics","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0966979524000992","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Considering the service safety for TiAl alloy under thermal shock, the effect of thermal shock temperature and cycles on micro-structural degeneration and mechanical properties were studied. The results show that the vertical decomposition of α2→β0 phase transition occurs in α2 lamellae if the single thermal shock temperature increases to 1000 °C or the thermal shock cycle increases to 10 times at 900 °C. Cracks form during the thermal shock progress as the single thermal shock temperature increases to 1000 °C or the number of thermal shocks is 5 times at 900 °C. Simultaneously, the flexural strength of samples decreases to 70% of the initial flexural strength under the same condition. It indicates that Ti–45Al–4Nb–1Mo-0.1B alloy fails as the single thermal shock temperature is above 1000 °C or the number of thermal shocks exceeds 5 times at 900 °C, and cracks generated during the thermal shock progress cause the dramatic deterioration in flexural strength. Meanwhile, the formed cracks are coarse, and the propagation path is relatively straight, which further deteriorates the flexural strength of the Ti–45Al–4Nb–1Mo-0.1B alloy. Besides, the nucleation and propagation of cracks change with the thermal shock temperature and cycles were analyzed. When the single thermal shock temperature is 1000 °C, the nucleation of cracks is not only in lamellar colony boundaries but also in α2/γ lamellar interfaces and the propagation path of cracks is relatively straight compared with the formation of cracks after 5 thermal shocks at 900 °C, because the thermal stress increases, and then cracks directly pass through lamellar colonies when the angle between lamellar orientation and crack propagation direction is about 90°.
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.