The Development of High Performance Ti-6Al-4V Alloy via a Unique Microstructural Design with Bimodal Grain Size Distribution
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The present work deals with the strengthening of Ti-6Al-4V alloy by creating a unique microstructure with bimodal grain size distribution, termed as “harmonic structure.” The Ti-6Al-4V compacts with harmonic structure design were successfully prepared via a powder metallurgy approach consisting of controlled mechanical milling and spark plasma sintering of the pre-alloyed Ti-6Al-4V powders. The microstructural evolution at each stage of processing has been investigated to establish a correlation between the processing conditions and the microstructural evolution. The Ti-6Al-4V compacts with heterogeneous harmonic structure exhibited better mechanical properties as compared to their homogeneous fine/coarse-grained counterparts. An attempt has also been made to explain the deformation mechanism of the harmonic-structured Ti-6Al-4V specimens with the help of the experimental evidences. The superior mechanical properties of the harmonic structure Ti-6Al-4V were found to be related to the peculiar topological distribution of strong fine-grained and ductile coarse-grained regions, which promotes uniform distribution of strain during plastic deformation and results in improved mechanical properties by avoiding the localized plastic deformation in the early stages of deformation.
KeywordsDigital Image Correlation Spark Plasma Sinter Severe Plastic Deformation Milled Powder Sintered Compact
This research was supported by the Japan Science and Technology Agency (JST) under Collaborative Research Based on Industrial Demand “Heterogeneous Structure Control: Toward Innovative Development of Metallic Structural Materials,” and by the Grant-in-Aid for Scientific Research on Innovative Area, “Bulk Nanostructured Metals,” through MEXT, Japan (contract No. 22102004). These supports are gratefully appreciated.
- 3.R. Boyer, G. Welsch, and E.W. Collings: Materials Properties Handbook: Titanium Alloys, ASM International, Materials Park, OH, 1994, pp. 483-636.Google Scholar
- 41.M.A. Sutton, J.J. Orteu, and H. Schreier: Image Correlation for Shape, Motion and Deformation Measurements, Springer, NY, USA, 2009, pp. 1-321.Google Scholar
- 45.http://www.daido.co.jp/en/products/titanium/medical.html. Accessed 18 Aug 2014.