Environmental Degradation of Additively Manufactured Alloys: Perspective, Challenges and Opportunities of Additively Manufactured Alloys in Corrosive Environments / High Temperature Oxidation and Corrosion
Sponsored by: TMS Structural Materials Division, TMS: Corrosion and Environmental Effects Committee
Program Organizers: Kinga Unocic, Oak Ridge National Laboratory; Luke Brewer, University of Alabama; Sebastien Dryepondt, Oak Ridge National Laboratory; Michael Kirka, Oak Ridge National Laboratory; Jenifer Locke, Ohio State University; Xiaoyuan Lou, Purdue University
Wednesday 2:00 PM
February 26, 2020
Room: 7A
Location: San Diego Convention Ctr
Session Chair: Kinga Unocic, Oak Ridge National Laboratory; Sebastien Dryepondt, Oak Ridge National Laboratory
2:00 PM Keynote
Examples of and Opportunities for Tailoring Corrosion Behavior of Materials via Additive Manufacturing: Kurt Terrani1; 1Oak Ridge National Laboratory
There exists a myriad of additive manufacturing methods to realize metals and ceramics in complex geometry relevant to energy applications. Corrosion behavior of a ceramic, SiC, and a metal, 316L stainless steel, in environments pertaining to nuclear energy applications of these materials is discussed as examples. More importantly, a discussion on opportunities for exploiting inherent characteristics of additive manufacturing to tailor the behavior of materials in corrosive environments is offered.
2:35 PM Invited
Segregation and Microstructural Factors Affecting the Oxidation Behavior of IN 625 Made by Additive Manufacturing: Brian Gleeson1; Grace Venessa de Leon Nope1; Guofeng Wang1; 1University of Pittsburgh
This presentations overviews efforts to better understand of the role of Nb and Mo segregation on the early-stage oxidation behavior of IN625 prepared by by additive manufacturing (AM), with comparisons to the wrought counterpart. To accomplish this, detailed microstructural characterization was conducted to quantify the nature and extents of Nb and Mo segregation, and oxidation behavior in air was assessed in the temperature range 650-950°C for up to 20h. The measured scaling kinetics were correlated with the scale structures and the subsurface composition and phase changes in the alloy owing to thermal and selective oxidation processes.
3:00 PM
High Temperature Air Oxidation Behavior of Haynes 282 Processed by Electron Beam Melting (EBM): Marie Romedenne1; Rishi Pillai1; Sebastien Dryepondt1; Padraig Stack2; 1Oak Ridge National Laboratory; 2Akron University
Additive manufacturing (AM) aim to complement or replace conventional and costly machining or production processes. While the current focus is on the evaluation of mechanical properties of as fabricated or heat-treated materials, the oxidation behavior of AM materials is rarely investigated. The oxidation behavior of two Haynes 282 variants: one as fabricated by EBM and one after standard heat treatment was evaluated and compared with the cast and homogenized Haynes 282. Thermogravimetric analyses during 100 h exposure at 750, 800 and 950 °C and furnace exposures at 750 and 950 °C for durations up to 1000 h were performed. The oxidation behavior was characterized as a function of temperature, microstructure, composition of the alloy and heat treatment.
3:20 PM
High Temperature Corrosion of Additively Manufactured Inconel 625: Gouri Bhasale1; Aarush Sood1; Shashi Singh1; Amit Pandey2; Amber Shrivastava1; 1Indian Institute of Technology Bombay; 2Ansys Inc.
Inconel alloys are used for the components of gas turbine, heat exchanger and pressure vessels, etc., in aerospace, nuclear, chemical processing and similar industries. In these applications, components made of Inconel are subjected to high temperatures and very corrosive environment. With the advent of additive manufacturing, components with relatively complex geometries can be fabricated. The objective of this work is to investigate the high temperature corrosion characteristics of additively manufactured (AM) Inconel 625. The specimens are exposed to 700oC and 900oC for different time periods. Upon cooling the samples to the room temperature, the weight loss is examined. Post characterization of Inconel 625 specimens are conducted using scanning electron microscopy and energy dispersive X-Ray spectroscopy to identify the corrosion products and their distribution. This presentation will highlight the effect of specimen density (due to porosity) as a result of AM process and its comparison with commercial Inconel 625 results.
3:40 PM Break
4:00 PM
High Temperature Oxidation Behavior of Additively Manufactured Inconel 625 Superalloy in Two Directions: Sedigheh Rashidi1; Amit Pandey2; Rajeev Kumar Gupta1; 1University of Akron; 2Ansys, Inc
High temperature oxidation behavior of Inconel 625 produced by Selective laser melting in longitude and transverse directions was studied and compared with that of the wrought alloy. Oxidation tests were performed on alloys at 850 and 1000 °C in laboratory air in order to evaluate their oxidation resistance. X ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy were used to characterize the oxidation behavior. The experimental results revealed that oxide scales of all superalloys were similar in nature and morphology with small differences due to additive manufacturing. A slow growing, continuous and well adherent chromia oxide scale on the all alloys surface formed which protected the alloy against rapid oxidation attack. the growth of the chromia base oxide scale resulted in oxidation- induced depletion in the subsurface zone of the alloy.
4:20 PM Invited
High Temperature Oxidation and Phase Transformations in γ-TiAl Produced by Additive Manufacturing: Radoslaw Swadzba1; 1Research Network ŁUKASIEWICZ Institute for Ferrous Metallurgy, Poland
γ-TiAl intermetallics have recently been successfully applied on low pressure turbine blades of modern aircraft engines due to their low density, high specific strength and creep resistance, all of which make them excellent alternatives for Ni-based superalloys. In this paper the results of investigations are presented concerning the oxidation behavior, microstructure evolution and phase transformations that occur within a 48-2-2 γ-TiAl alloy produced by EBM. Analytical tools such as EBSD as well as quantitative XRD were employed to study the phase transformations taking place during long-term high temperature exposure up to 3000 hours at 750 and 850 °C in 500 hour intervals. The oxidation behavior of the alloy was studied under cyclic and isothermal oxidation conditions at 750 and 850 °C up to 3000h. Special effort has been done in order to perform a detailed investigation of the growth of protective oxide scales using high resolution STEM, EFTEM and EELS.
4:45 PM
Improving the Corrosion Performance of Additively Manufactured 316L via Optimized SLM Processing Parameters: Joseph Sopcisak1; Steven Storck1; Rengaswamy Srinivasan1; Morgan Trexler1; 1The Johns Hopkins University Applied Physics Laboratory
Due to the complex thermal profiles associated with consolidation of material on small length scales, additive manufacturing (AM) has many advantages over conventional manufacturing methods such as the ability to produce free-form complex shapes and materials with unique properties. Nevertheless, the implementation of AM into corrosive environments is ultimately limited by the reduction in corrosion performance of AM parts when compared to their conventionally manufactured counterparts. Improving the corrosion resistance of AM parts can be unlocked with precise control of machine parameters. In this effort, laser parameters were adjusted to optimize corrosion performance. Laser power, speed, point distance, and hatch spacing were systematically varied in a laser powder bed fusion (L-PBF) system and were consolidated via selective laser melting (SLM) to establish which parameters influenced pitting performance. Samples showed clear evidence relating laser process parameters to grain structure, meltpool boundaries, and their role in nucleation and growth of pitting corrosion.
5:05 PM
High Temperature Oxidation Behavior of 316L Austenitic Stainless Steel Manufactured by the Selective Laser Melting: Zhyuan Liang1; 1Xi'an Jiaotong University
High temperature oxidation of 316L austenitic stainless steel manufactured by the selective laser melting (SLM) was investigated. Oxidation tests of 316L and 316L made by SLM were conducted in a horizontal heating tube in experimental air at 600 ℃ up to 500 h. Multi characterization techniques including X-ray diffraction, scanning electric microscope, Raman spectra, and energy dispersive spectrometer were used to confirm the compositions and distribution of corrosion products. Results show that oxidation kinetics of investigated materials followed a sub-parabolic oxidation law. The weight gain of 316L made by SLM was slightly higher than that of 316L. Original surfaces of 316L and 316L made by SLM were attributed to the higher weight gains. Surface grinding of investigated materials was beneficial for their corrosion resistance by developing an intact Cr-rich oxide scale.