Mechanical Response of Materials Investigated through Novel In-situ Experiments and Modeling: Session VII
Sponsored by: TMS Structural Materials Division, TMS: Thin Films and Interfaces Committee, TMS: Advanced Characterization, Testing, and Simulation Committee
Program Organizers: Saurabh Puri, VulcanForms Inc; Amit Pandey, Lockheed Martin Space; Dhriti Bhattacharyya, Australian Nuclear Science and Technology Organization; Dongchan Jang, Korea Advanced Institute of Science and Technology; Jagannathan Rajagopalan, Arizona State University; Josh Kacher, Georgia Institute of Technology; Minh-Son Pham, Imperial College London; Robert Wheeler, Microtesting Solutions LLC; Shailendra Joshi, University of Houston
Thursday 8:30 AM
March 18, 2021
Room: RM 17
Location: TMS2021 Virtual
Session Chair: Dhriti Bhattacharyya, Australian Nuclear Science and Technology Organization
8:30 AM Keynote
Microstructural Influences on Grain Boundary Sliding in High Purity Aluminum
: Marissa Linne1; Thomas Bieler2; Samantha Daly3; 1University of Michigan; Lawrence Livermore National Laboratory; 2Michigan State University; 3University of California at Santa Barbara
The presented work investigates grain boundary sliding (GBS), a grain boundary-enabled deformation mechanism, and its relationship with local plasticity and microstructural neighborhood. GBS is characterized experimentally at grain boundaries in 99.99% aluminum with a through-thickness, coarse-grained microstructure deformed in tension at 190 °C. High-resolution strain fields and microstructural information were measured to examine the influence of microstructural neighborhoods on interactions between GBS and slip transmission and strain localization. The findings include (1) direct transmission and GBS were anti-compatible and facilitated by opposing boundary types (low misorientation and high energy grain boundaries respectively); (2) increased GBS activity was correlated with decreased indirect transmission behavior and (3) GBS accommodation at triple junctions was enabled by intragranular plasticity. This work provides insight into the nature of GBS activity and can be used to identify strain transfer criteria that can lead to improved GBS-sensitive crystal plasticity models. Prepared partially by LLNL under Contract DE-AC52-07NA27344.
9:10 AM
In-situ Analysis of Powder Bed Quality during Selective Laser Melting: Tan-Phuc Le1; Matteo Seita1; 1Nanyang Technological University
The powder bed quality—including layer thickness uniformity and powder packing density—has a direct effect on the performance and consistency of parts produced via powder bed fusion (PBF) processes. However, in-situ monitoring of these quantities is challenging because it requires assessing the 3-D configuration of powder particles across the entire powder bed. In this work, we employ a “powder bed scanner” technique to capture particle-level resolution images of the entire powder bed surface during the re-coating process, which we analyze to infer 3-D information. Using this technique, we map variations in layer thickness and particle density as a function of powder conditions (e.g. virgin or recycled) and re-coating velocity during selective laser melting of stainless steel 316L specimens. We correlate this site-specific information with the material’s mechanical properties and propose strategies to optimize part performance depending on powder conditions.
9:30 AM
Non-linear Reversible Behaviour of Metallic Alloys at Low Stresses: Jaji Naveena Chamakura1; Vera Popovich1; Jilt Sietsma1; 1TU Delft
The elastic material behaviour of metals is more complex than the generally assumed linear behaviour. This is primarily due to the reversible behaviour of dislocations. This work aims to investigate the fundamentals of non-linear stress-strain reversible behaviour at low stresses of industrial-grade metal alloys. Mechanical testing is performed in various relevant loading modes with a focus on the measurement of small strains and corresponding stresses, occurring in the elastic regime. The non-linearity is quantitatively analyzed in microstructural aspects, as opposed to the common approximation of an empirical determination of apparent Young’s modulus. The detailed analysis of the experimental evidence on the non-linear elastic behaviour, hysteresis and microplasticity will be used to further investigate and extend model descriptions that are based on the dislocation behaviour of the material. The physical basis of the models will provide the possibility of application for predictive and quantitative modelling of low-stress behaviour in various metals.
9:50 AM
Creation of Strength Diagrams of Aluminum Flat Products, Dependent on the Different Thermomechanical Processes: Kaan Ipek1; Emel Çalışkan2; Derya Dispinar3; 1Teknik Aluminyum San. A.Ş.; 2Istanbul University; 3Istanbul Teknik University
Optimization of the desired process parameters can be realized by modeling the production processes. In this study, it is aimed to investigate the effect of cold rolling and annealing process on the 1050, 3005, 3105, 8006 aluminum commercial alloys produced by twin roll casting. Cold rolling process were applied at different deformation rates between 25% and 95% from the casting thicknesses. Also annealing processes were applied between 220 and 480 degrees were obtained at 20 degree intervals. Tensile strength, hardness and electrical conductivity have been carried out on materials subjected to different cold rolling and anneling processes. Formabilities of materials were examined with the Erichsen test. As a result of the experiments, mechanical strength limit values were obtained depending on the different cold rolling and annealing processes of the materials and process optimization was carried out by examining them with the help of regression models.
10:10 AM
Microscale Insight into the Effect of Twinning on Fracture in a Manganese Steel: Xinzhu Zheng1; Ankit Srivastava1; 1Texas A&M University
Manganese rich austenitic twinning induced plasticity steels offer high strength and ductility. These steels exhibit extremely high strain hardening rate with an upward curvature in the stress – strain response. The high strain hardening rate in these materials is largely associated with the activation of twinning. In this work, we attempt to understand the effect of twinning on the fracture response of a manganese rich austenitic steel. To this end, in-situ tensile tests of smooth and notched sheet specimens of single and poly crystals of the steel of interest are carried out. The crystallographic orientations of the single crystal specimens are chosen to selectively activate single slip, multiple slip or twinning. Furthermore, our in-situ tests allow us to simultaneously capture macroscopic response, microstructure evolution and the distribution of microscale strains. This presentation will focus on the results correlating deformation mechanism, microscale deformation and the fracture response of the material.
10:30 AM
Surface Erosion of Spacecraft by High-velocity Regolith Impacts to Simulate Wind Storms on Martian Surfaces: Nicole Bacca1; Cheng Zhang1; Arvind Agarwal1; 1Florida International University
Recent advances and interests in space exploration have led to important questions on the effect erosion can play on space vehicles. Those expected to be on Mars long term are exposed to extreme environmental conditions, where the abrasive Martian regolith should be taken into account to consider the erosion and degradation of aerospace materials. By a uniquely in-house designed testing rig with high-velocity regolith impacts to metals and polymers commonly used for spacecrafts, a wind storm on Martian surfaces can be simulated. The impact velocity and the angle of impact will be recorded. The eroded surface will be characterized both qualitatively and quantitatively. These experiments will allow for an understanding of erosion behavior of these materials from Mars Regolith, and create a prediction of how these materials could withstand the environmental conditions of Mars.