Late News Poster Session: On-Demand Fundamentals and Characterization Poster Session
Program Organizers: MS&T Administration, MS&T PCC

Friday 8:00 AM
October 22, 2021
Room: On-Demand Poster Hall
Location: MS&T On Demand

Extrinsic Size Effects on Fracture Behaviour of Copper: Hrushikesh Sahasrabuddhe¹; Anirban Patra¹; Nagamani Jaya Balila¹; ¹India Institute of Technology Bombay
     Size effects are well known to influence the mechanical behaviour of materials. While literature exists on size effects (extrinsic v/s intrinsic) on strength, the effect of extrinsic specimen size effects on fracture is not well quantified. The objective of the present study is to elucidate the influence of specimen thickness on the plane stress fracture toughness (J_c) of materials under elastic-plastic domain.Hot-rolled Cu sheets of constant grain size and changing thickness are tested using single edge notch tension (SENT) geometry. The relevant non-dimensional factors for the same are derived from numerical simulations by inputting the exact stress-strain response for each thickness. Experimental quantification of J_c is made using CTOD and the load-unload techniques for increasing surface area to volume ratios. J_c obtained from both techniques show a significant dependence on the extrinsic dimension which is explained through a dislocation exhaustion model.

Poster
Microstructural Conditioning to Reveal Prior Austenitic Grain Using the Oxidation Method: David Fernandez-Sanchez¹; Alexis Gallegos-Perez¹; Octavio Vázquez-Gómez¹; Pedro Garnica-Gonzalez¹; Hector Vergara-Hernandez¹; Antonio Oliver-Reynoso²; ¹Tecnológico Nacional de México / I.T. Morelia; ²Tecnológico Nacional de México/ I.T. Morelia
    The microstructure of an experimental 1Cr-1Mo-0.3V steel was conditioned by applying heat treatments to reveal prior austenitic grain size, since the predominant microstructure is a combination of ferrite, acicular ferrite and bainite promoted by alloying elements contained in the steel. The specimens surfaces heat treated under homogenized-annealed and homogenized-normalized conditions were prepared through the oxidation and chemical etching method with a solution of hydrochloric acid, picric acid and ethyl alcohol (Vilella), before and after quenching, respectively. Microstructures obtained were analyzed by optical microscopy depending on treatment condition. Finally, it was determined that the revealing of prior austenitic grain is sensitive to the initial microstructure, as well as the exposure time during chemical etching, standing out the grain refinement in the microstructure despite previous conditioning.

Nanoindentation Studies on Friction Stir Processed Dual Phase High Entropy Alloy : Neelam Meena¹; Gourav Rao²; Nithyanand Prabhu¹; ¹IIT BOMBAY; ²Naval Materials Research Labroatory
    Multi-phase High Entropy Alloys (HEAs) are a new class of materials with excellent combination of properties. In the present work, a TWIP/TRIP assisted dual phase interstitial Fe49.5Mn30Co10Cr10C0.5 HEA is subjected to single-pass and multi-pass friction stir processing. A fine grain microstructure is obtained due to the severe plastic deformation produced as a result of friction stir processing. Nanoindentation is performed to characterize the microstructural dependent mechanical properties of different processing zones, viz., the stir zone, the heat affected zone and the thermo mechanical heat affected zones on the advancing and retreating sides in samples subjected to both single pass and multi pass friction stir processing. Hardness and elastic modulus of multi pass friction stir processed sample is found to be better than that of single pass.