Titanium Processing and Applications: Session II
Sponsored by: MS&T Organization
Program Organizers: Rodney Boyer
Thursday 2:00 PM
October 20, 2011
Room: D232
Location: Greater Columbus Convention Center
Session Chair: Hamish Fraser, The Ohio State University
2:00 PM
Performance of Palladium Coatings on Titanium Grade 2: Kavitha Tummala1; Sean Brossia1; Sharon Rad2; 1DNV USA; 2Ben-Gurion University of the Negev
Titanium alloys are widely used in chemical industry due to their good chemical resistance to corrosion and ability to withstand high temperatures. It is well recognized that adding small quantities of palladium (and other rare earth elements) enhances the corrosion resistance even when chlorides and non-oxidizing acids are present. Though there is a desire to utilize these alloys, in some cases their use is curtailed due to cost constraints. The current studies are aimed at determining whether a thin palladium coating on commercially pure titanium provides similar corrosion performance.
2:20 PM Cancelled
Micro-Texture Evolution of Ti in Multilayer Sheets Processed by Accumulative Roll Bonding: Liming Zhou1; Viola Acoff1; 1The University of Alabama
Electron backscattered diffraction (EBSD) was utilized to characterize the micro-texture evolution of Ti layers in multilayered sheets developed by accumulative roll bonding. Twining under this case is still a dominative deformation mechanism even in individual layer reduction exceeding 70% reduction due to neighboring high stacking fault energy material Al. Basal plane poles deviated about 34 degrees about the transverse direction (TD) along the rotation axis of rolling direction (RD) after deformation, anisotropic tendencies tended to distribute along <10-10> fiber along RD, and partial basal plane texture diminished or rotated 30 degrees to {0001} <2-1-10>. The Schmid factor, including basal slip, prismatic, and pyramid slip as a function of individual layers, Von Mise strain, and relative frequency are generated to study activated slip systems under this special deformation case. The results were compared to the deformation characteristics for bulk commercial Ti.
2:40 PM
Titanium for Capacitive Energy Storage: Gerhard Welsch1; 1CWRU
The following topics will be addressed: Purity and doping of titanium, surface enhancement processing and growth and structure of oxide film to serve as a dielectric.
3:00 PM
Mechanical Properties and Deformation in Multi-Scale Nanostructured Cu and Ti: Yonghao Zhao1; Y. Li1; Troy Topping1; Y.T. Zhu2; R. Z. Valiev3; E.J. Lavernia1; 1University of California Davis; 2North Carolina State University; 3Institute of Physics of Advanced Materials, Ufa State Aviation Technical University, 12 K. Marksa str., Ufa 450000, Russia
Multi-scale nanostructured materials containing bi-/multi-modal grain size distributions can be engineered to display unusual balance of properties, such as strength and ductility. Despite well documented reports of enhanced ductility in multi-scale nanostructured materials, systematic identification of the quantitative relationship between mechanical properties and microstructures as well as underlying deformation mechanisms has not been accomplished. In this work, we selected high-purity Cu and commercial pure Ti as a model material system in an effort to elucidate the underlying mechanisms. The bi-/multi-modal Cu and Ti were prepared by equal-channel-angular pressing (ECAP) and subsequent annealing. Transmission electron microscopy (TEM) in combination with tensile testing are used to characterize the deformation mechanisms and mechanical behavior.
3:20 PM Break
3:40 PM
Characterization of "Check-Mark" Alpha Precipitate in Titanium Alloys Using 2D and 3D Characterization Techniques: Michael Presley1; Daniel Huber1; John Sosa1; Brian Welk1; Yufeng Zheng1; Hamish Fraser1; 1The Ohio State University
Several authors have made observations of a characteristic “check-mark” α morphology observed in transformed prior β titanium grains; however, no satisfactory explanation has been put forth to characterize this morphological transformation, nor the effect it will have on the resultant microstructural morphology of α+β titanium alloys. For this work, “check-mark” shaped alpha precipitates have been observed in various commercial titanium alloys through precise heat treatment schedules designed to produce the characteristic α morphology on several size scales. This study characterized the “check-mark” alpha precipitate morphology as a precursor to the colony microstructure using (S)TEM and SEM for 2D analysis, as well as 3D analysis using serial section data sets collected with a Nova™ NanoLab 600 and RoboMet.3D
4:00 PM
High- Resolution SEM/(S)TEM Microstructural Characterization of Ti-6Al-4V Alloyed with Fe: Daniel Huber1; Brian Welk1; Travis Presley1; John Sosa1; Hamish Fraser1; 1The Ohio State University
Novel lightweight titanium alloys, given sufficiently low production costs, could benefit many products and applications extending past the current aerospace market. The purpose of this work was to survey and characterize the microstructure of a possible low-cost, metastable beta titanium alloy with Fe as the primary beta stabilizing element. Iron is significantly less expensive than current alloying additions and empirically functions as a potent beta stabilizer in titanium alloys; this phenomenon, however, is not well understood. To examine this phenomenon various thermomechanical treatments of alloys, expected to have a beta stability similar to and in excess of Ti - 5553, were chosen for characterization comparison. Specifically, alloys were composed of commercial Ti-6Al-4V alloyed with 4 and 6 Wt.% Fe. Advanced characterization was performed using HR-SEM and HR-(S)TEM for imaging and energy-dispersive spectroscopy(EDS) for chemical analysis.
4:20 PM
Investigation and Characterization of Second Phase Precipitation during Tempering of Martensitic Ti-6 Al -2 Mo -2 Cr -2 Sn -2 Zr -S by SEM and (S) TEM: Jonathan Orsborn1; Hamish Fraser1; Robert Williams1; Daniel Huber1; Yufeng Zheng1; 1The Ohio State University
Ti-6 Al -2 Mo -2 Cr -2 Sn -2 Zr –S (Ti-62222-S) is an alpha/beta titanium alloy developed, in part, for deep hardenability, or its propensity to form martensite using slower cooling rates than those required for similar alpha/beta Ti-alloys. This microstructural evolution allows for tempering of martensitic Ti-62222-S to produce refined and homogenous microstructures, even in large sections. Certain tempering procedures have been found to produce alpha+beta microstructures, in which alpha laths wholly contain presently unknown second phase precipitates, with a plate-like morphology. This work will discuss the effect of tempering on the evolution, structure, composition, and morphology of this unknown phase in Ti-62222-S through SEM, TEM and STEM characterization, in conjunction with EDS and EELS for chemical analysis.
4:40 PM
Microstructure Evolution during Controlled Dynamic Spheroidization of Ti-6Al-4V: Chan Hee Park1; Chong Soo Lee2; 1Korea Institute of Materials Science; 2Pohang University of Science and Technology
This study aimed to achieve enhanced room temperature strength and high temperature formability of Ti-6Al-4V by producing ultrafine-grained microstructure without imposing severe strains. For this purpose, conventional dynamic spheroidization process, the conversion from lamellar to equiaxed microstructure, was modified to suppress lath/grain coarsening during deformation. The formation of ultrafine-grained microstructure at relatively low strain was investigated by examining the microstructure evolution with straining and rationalized in the context of diffusion-based model.
5:00 PM
Phase Transformation Identification in Beta Titanium Alloys Using ETMT and SSDTA: Yufeng Zheng1; Robert Williams1; Boian Alexandrov1; Hamish Fraser1; 1The Ohio State University
Understanding the microstructural evolution in beta titanium alloys is necessary for tailoring material and mechanical properties of these alloys. Due to a combination of high strength and great ductility, beta titanium has developed as a promising candidate for future use in biomedical implant as well as for aerospace applications. The omega phase and beta prime phase are widely believed to be precursors to the precipitation of alpha from an intermediate temperature range. Using state of the art equipment, the phase transformation sequence of beta titanium during the heating process was studied by electrical resistivity measurements using an Electro-Thermal-Mechanical Tester(ETMT). Using high resolution transmission electron microscopy to characterize the onset of alpha precipitate formation in Ti-Mo binary alloy and Ti-5Al-5Mo-5V-3Cr allowed salient features to be studied in details. The phase transformation sequence is also compared with the result of single sensor differential thermal analysis(SSDTA).
5:20 PM
The Technological features of Titanium Aluminides Retrieving by SHS-compacting: Borys Sereda1; Aleksandr Zherebtsov1; Dmytro Sereda1; 1ZSEA
The research of deformation processing at titanium aluminides processed by SHS-compacting are discussed. The dependence of compacting pressure on ingot’s geometrical size and density is established for various types of titanium aluminides. The kinetic force parameters of pressing process are modeled and experimentally confirmed. Also research on determination of different ingot zones compacting during pressing are executed. It is established that central zone of ingots are compacted more than outer zone. The influence of radial pressure on equipment during SHS-compacting is analyzed. The non-isostatic deformation coefficient during pressing of titan aluminides was established. It was determined that SHS-compacting depends not only on energy-force parameters but also on temperature, phase structure and aggregative state of synthesized product. So the model of SHS-compacting depends on many factors and research can directly solve the question of heat-resistant materials retrieving on Ti-Al base.