{"title":"On the Microstructural Evolution and Cracking Behavior of a Titanium Aluminide Alloy During Selective Laser Melting.","authors":"Xintian Wang, Fujin Qu, Chunlei Qiu","doi":"10.1089/3dp.2022.0267","DOIUrl":null,"url":null,"abstract":"<p><p>Selective laser melting of Ti-48Al-2Cr-2Nb usually ends up with serious cracking. The cracking mechanism, however, remains elusive. In this study, both bulk samples and samples containing only several layers were prepared and investigated. It is shown that a freshly built layer is dominated by single α<sub>2</sub> phase. γ started to form from α<sub>2</sub> during subsequent thermal cycling due to reheating effects and its volume fraction increased continuously with increased thermal cycles. The γ phase contains higher geometrically necessary dislocation (GND) density than α<sub>2</sub>. This could be due to its relatively lower hardness and higher thermal expansion coefficient, which made it easier to deform under stresses. With higher GND and thus probably higher distortion energy, the γ experienced more extensive recrystallization than α<sub>2</sub> during reheating. Cracks are more liable to initiate from the interior of α<sub>2</sub> or the γ/α<sub>2</sub> interfaces, which could be due to incompatible deformation between the two phases.</p>","PeriodicalId":54341,"journal":{"name":"3D Printing and Additive Manufacturing","volume":null,"pages":null},"PeriodicalIF":2.3000,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10880645/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"3D Printing and Additive Manufacturing","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1089/3dp.2022.0267","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/2/15 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"ENGINEERING, MANUFACTURING","Score":null,"Total":0}
引用次数: 0
Abstract
Selective laser melting of Ti-48Al-2Cr-2Nb usually ends up with serious cracking. The cracking mechanism, however, remains elusive. In this study, both bulk samples and samples containing only several layers were prepared and investigated. It is shown that a freshly built layer is dominated by single α2 phase. γ started to form from α2 during subsequent thermal cycling due to reheating effects and its volume fraction increased continuously with increased thermal cycles. The γ phase contains higher geometrically necessary dislocation (GND) density than α2. This could be due to its relatively lower hardness and higher thermal expansion coefficient, which made it easier to deform under stresses. With higher GND and thus probably higher distortion energy, the γ experienced more extensive recrystallization than α2 during reheating. Cracks are more liable to initiate from the interior of α2 or the γ/α2 interfaces, which could be due to incompatible deformation between the two phases.
期刊介绍:
3D Printing and Additive Manufacturing is a peer-reviewed journal that provides a forum for world-class research in additive manufacturing and related technologies. The Journal explores emerging challenges and opportunities ranging from new developments of processes and materials, to new simulation and design tools, and informative applications and case studies. Novel applications in new areas, such as medicine, education, bio-printing, food printing, art and architecture, are also encouraged.
The Journal addresses the important questions surrounding this powerful and growing field, including issues in policy and law, intellectual property, data standards, safety and liability, environmental impact, social, economic, and humanitarian implications, and emerging business models at the industrial and consumer scales.