Advances in Titanium Technology: Session VIII
Sponsored by: TMS Structural Materials Division, TMS: Titanium Committee
Program Organizers: Yufeng Zheng, University of North Texas; Zachary Kloenne, Ohio State University; Fan Sun, Cnrs Umr 8247 - Chimie Paristech Psl; Stoichko Antonov, National Energy Technology Laboratory; Rongpei Shi, Harbin Institute of Technology (Shenzhen)
Thursday 2:00 PM
March 23, 2023
Room: Cobalt 500
Location: Hilton
Session Chair: Zachary Kloenne, Ohio State University
2:00 PM
Exploration of Young’s Modulus and Acoustic Velocity Variation in Ti-5Al-5V-5Mo-3Cr Metastable Phase Transitions: Ruth Sunderman1; Maria Quintana1; Andrew Temple1; Ben Brown2; Thomas Ales1; Peter Collins1; 1Iowa State University; 2Kansas City National Security Campus
Subtle changes in heat treatments of β stabilized titanium alloys have been reported to produce dramatic differences in tensile strength and ductility due to metastable phase transitions. Ideally, these changes in mechanical properties could be detected by means of a nondestructive testing technique. The relationship between bulk acoustic wave velocity and Young’s modulus is well known, but this relationship will be explored in the context of detecting subtleties of beta-stabilized titanium alloy 5553 wrought and additive manufacturing samples caused by heat treatment-induced metastable phase transitions. Conventional acoustic measurements indicate wave speed differences among a variety of heat treatment conditions and these measurements will be compared to spatial variations of properties as measured using grain orientation mapping collected with Spatially Resolved Acoustic Spectroscopy and subscale (i.e., micro, nano) indentation modulus measurements.
2:20 PM
Effects of Short-time Solution Treatment and Subsequent Short-time Annealing on the Microstructure and Deformation Behavior of Ti-6Al-4V Sheet Metal: Nina Pfeffer1; Stefanie Jäger1; Lukas Kytzia1; Heinz Werner Höppel1; Mathias Göken1; 1Friedrich-Alexander-Universität Erlangen-Nürnberg
The phase and TTT diagrams of the Ti-6Al-4V system allow the development of a new quenching forming process for a more energy and material efficient production of sheet metal parts. This new process is comparable to the press-hardening process well known for steels, but also includes a subsequent short-time annealing step. To gain a fundamental understanding, short-time heat treatments were applied to Ti-6Al-4V sheet metal to produce different STQ (solution treated water quenched) and STA (solution treated annealed) states in this work. The effects of a) solution treatment temperature (below Tβ) and time followed by water quenching and b) the annealing temperature and time on microstructure and mechanical properties were focused on.By the systematic variation of applied STQ and STA processing parameters, dominating effects on the microstructure and consequently on the quasi-static as well as cyclic properties were evaluated. The results reveal a high potential for future technical applications.
2:40 PM
A Microstructure-informed Crystal Plasticity Based Constitutive Model for DED Ti6Al4V Alloy: Chamara Herath1; Kavindu Wijesinghe1; Ajit Achuthan1; 1Clarkson University
The development of a hierarchical microstructure-informed crystal plasticity based constitutive model for directed energy deposited (DED) Ti6Al4V is discussed. DED Ti6Al4V often exhibits a Widmanstätten microstructure, which is a dual-phase microstructure consisting of α and α' palates in a β matrix arranged in colonies within grains. In addition, the microstructure also consists of grain boundary α surrounding the grains. The developed microstructure-informed constitutive model accounts for the geometric and mechanistic effects of the Widmanstätten microstructure and grain boundary α by explicitly considering these features in a 3D representative microstructure. Homogenization schemes are developed to effectively implement the constitutive model on a finite element analysis (FEA) framework. The anisotropy is realized as a natural outcome of a preferred alignment of α and α' palates inside colonies with respect to the build direction. The model is experimentally validated by obtaining the stress-strain behaviors in both the build and scan directions.
3:00 PM
Effect of Volumetric Defects on the Fatigue Behavior of Laser Powder Bed Fused Ti-6Al-4V: Muztahid Muhammad1; Shuai Shao1; Nima Shamsaei1; 1Auburn University
Additively manufactured parts contain process-induced volumetric defects which can be detrimental to fatigue performance. This study investigated the effect of defects on the fatigue behavior of the laser powder bed fused (L-PBF) Ti-6Al-4V specimens. Cylindrical rods of L-PBF Ti-6Al-4V were fabricated with large variations (total six sets) in process parameters to induce different types of defects. After stress relief, cylindrical rods were removed from the build plates and machined to standard fatigue test specimens. A high resolution X-ray Computed Tomography machine was employed to analyze the defect distribution of selected specimens resulting from each set of process parameters before fatigue testing. Fully-reversed force-controlled fatigue tests were conducted at room temperature using a servo-hydraulic load frame. A scanning electron microscope was utilized to analyze the microstructure and fracture surfaces. The size and shape of the crack initiating defects were attempted to be correlated with the measured fatigue properties.