Advanced Thermo-mechanical Characterization of Materials with Special Emphasis on In Situ Techniques: Poster Session
Sponsored by: TMS Structural Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Nanomechanical Materials Behavior Committee, TMS: Thin Films and Interfaces Committee
Program Organizers: Amit Pandey, LG Fuel Cell Systems Inc.; Sanjit Bhowmick, Hysitron; Jeff Wheeler, ETH Zurich; María Teresa Pérez Prado, IMDEA Materials Institute; Robert Wheeler, MicroTesting Solutions LLC; Josh Kacher, Georgia Tech

Tuesday 6:00 PM
February 28, 2017
Room: Hall B1
Location: San Diego Convention Ctr

L-10: Deformation Characteristics of NiTi Alloys: Sujith S1; Indrani Sen1; 1IIT Kharagpur
    In the present work, indentation study has been performed on NiTi alloy with different heat treatment conditions and on different grain orientations. The alloy of composition 50.9 Ni-Ti (at. %) has made precipitated and precipitated free condition. It is evident that change in phase transformation temperatures occur in NiTi owing to the heat treatment conditions. Deformation behavior of the alloys are next characterized by implementing micro- and nano-indentation techniques for range of load for getting idea about indention size effect. Presence of precipitate cause higher hardness value for precipitated sample. Such precipitates hinder the reversible phase transformation leading to higher remnant depth ratio (RDR) and poorer pseudoelasticity. Nano indentation on grains with different orientation surface normal revealed the orientation dependence of pseudoelasticity for the material. A detailed analysis is performed to correlate firmly the microstructure with the mechanical properties for this category of shape memory alloys.

L-11: High Temperature Dynamic Mechanical Response of Titanium Alloys: Sindhura Gangireddy1; Steven Mates1; 1NIST
    Titanium alloys are widely used in aerospace industry. A constitutive material model is crucial in understanding component failure as well as in the improvement of manufacturing processes such as high speed machining. Numerous studies are happening on mathematical modeling and simulation of such conditions, but they are all only as good as the material model used. Experiments were conducted at high temperatures under dynamic mechanical and thermal loading conditions, creating close simulation of extreme THERMO-MECHANICAL events such as explosive impact, high speed machining etc. The constitutive response of Ti-6Al-4V alloy and CP-Ti will be presented from a wide range of testing conditions: room temperature - 1200C, 0.1-0.3 plastic strains and 0.000001-3000 strain rate. Effect of time dependent microstructural evolution (annealing, grain growth, phase transformation) and grain morphology (globular, lamellar, widmanstatten, martensitic) was also investigated. All results are very recent from last year study conducted at NIST.