High entropy alloys (HEAs) are a new class of solid solution alloys that contain multiple principal elements and possess excellent mechanical properties, from corrosion resistance to fatigue and wear resistance. Even more recently, twinning induced plasticity (TWIP) and transformation induced plasticity (TRIP) non-equiatomic high entropy alloys have been engineered, promising increased strength and ductility as compared to their equiatomic counterparts. However, impact and fracture resistance of these HEAs has not been studied as much as their other mechanical properties. In this thesis, the hardness, tensile properties, and Charpy impact energy of Al0.3CoCrFeNi, a TWIP HEA, and 50Fe-30Mn-10Co-10Cr (at.%), a TRIP HEA, was explored. First, three processing conditions, (1) as-received, (2) recrystallized, and (3) peak hardness, were chosen for each alloy and verified with Vickers microhardness measurements. Next, the tensile properties of each alloy and condition were investigated. Charpy impact specimen size was then selected based on the final plate thickness, and the machined samples were tested. Plastic zone size and change in sample thickness in the deformed region of each condition after testing was measured. Post-impact test inspection of the samples in all conditions showed that the samples were in tension near the V-notch root and in compression at the impact surface. Plastic zone size is seen to change as a function of distance from the V-notch root moving towards the impact surface in conditions that exhibited higher ductility. Overall, the TWIP alloy displayed high fracture resistance, and further microstructural optimization will likely increase the fracture resistance of these alloys.
| Identifer | oai:union.ndltd.org:unt.edu/info:ark/67531/metadc1538702 |
| Date | 08 1900 |
| Creators | Zellner, Samantha R |
| Contributors | Mishra, Rajiv, Reidy, Richard F., Mukherjee, Sundeep |
| Publisher | University of North Texas |
| Source Sets | University of North Texas |
| Language | English |
| Detected Language | English |
| Type | Thesis or Dissertation |
| Format | ix, 61 pages, Text |
| Rights | Use restricted to UNT Community, Zellner, Samantha R, Copyright, Copyright is held by the author, unless otherwise noted. All rights Reserved. |
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