A5079845699- Additive Manufacturing Materials and Processes
- Welding Techniques and Residual Stresses
- Additive Manufacturing and 3D Printing Technologies
- Corrosion Behavior and Inhibition
- High-Temperature Coating Behaviors
- High Entropy Alloys Studies
- Hydrogen embrittlement and corrosion behaviors in metals
- Non-Destructive Testing Techniques
- Magnesium Alloys: Properties and Applications
- Concrete Corrosion and Durability
- Aluminum Alloy Microstructure Properties
- Aluminum Alloys Composites Properties
- Advanced Materials Characterization Techniques
- Manufacturing Process and Optimization
- Metal and Thin Film Mechanics
- Polymer Nanocomposites and Properties
- Catalytic Processes in Materials Science
- Asphalt Pavement Performance Evaluation
- Conducting polymers and applications
- Advanced materials and composites
- Material Properties and Failure Mechanisms
- Probabilistic and Robust Engineering Design
- Advanced Welding Techniques Analysis
- Material Selection and Properties
- Advanced machining processes and optimization
Sandia National Laboratories
2018-2024
Sandia National Laboratories California
2019-2024
University of Virginia
2015-2020
The Ohio State University
2019
McCormick (United States)
2016-2018
The impact of microstructure and processing defects directed energy deposition (DED) 304L stainless steel on its corrosion behavior was investigated. Materials produced by DED with heat inputs 0.45 0.03 kJ/mm were compared to wrought 304L. Lack fusion pores in the material controlled breakdown potential (Eb) first order, reducing it up 400 mV versus base 0.6 M NaCl. hierarchal control these other features, nanoscale oxides δ-ferrite, features Eb is addressed.
Abstract Additively manufactured austenitic stainless steels exhibit numerous microstructural and morphological differences compared to their wrought counterparts that will influence the metals corrosion resistance. The characteristic as-printed surface roughness of powder bed fusion (PBF) steel parts is one these increases susceptibility localized corrosion. This study experimentally determines average breakdown potential (E b ) for PBF 316L in 6 finished states: as-printed, ground with SiC...
Abstract Assessing the lifetimes of alloys in humid, corrosive environments requires growth kinetic information regarding individual instances damage, e.g. pit rates. Corrosion rates measured at continuum scale using mass change convolute rate nucleation and growth, providing limited on local kinetics. The current study used in-situ X-ray computed tomography to measure pits aluminum over 100 h exposure a chloride environment. While grew relatively constant first hours after nucleation,...
Atmospheric corrosion of metallic parts is a widespread materials degradation phenomena that challenging to predict given its dependence on many factors (e.g. environmental, physiochemical, and part geometry). For with long expected service lives, accurately predicting the degree which will degrade performance especially difficult due stochastic nature damage spread across years or decades service. The Finite Element Method (FEM) computational technique capable providing accurate estimates...
Nanostructured titanium dioxide (TiO2) presents considerable potential as a photoanode in low cost, sustainable photoelectrochemical systems for solar water splitting. The wide band gap combined with the presence of trap states and reduced oxidation kinetics limit, however, photocurrent performance to only ∼1 mA cm–2. Increasing disorder crystal structure at surface, on other hand, has been proven increase light absorption via narrowing, conversion efficiency. In this work, anodized TiO2...
The development of additively-manufactured (AM) 316L stainless steel (SS) using laser powder bed fusion (LPBF) has enabled near net shape components from a corrosion-resistant structural material. In this article, we present multiscale study on the effects processing parameters corrosion behavior as-printed surfaces AM SS formed via LPBF. Laser power and scan speed LPBF process were varied across instrument range known to produce parts with >99 % density, macroscale trends interpreted...
The effect of relative humidity (RH) on the corrosion coarse-ground 304 stainless steel exposed for one year under sea salt particles was investigated. Total damage accumulation higher at 40% RH than 76% RH. At RH, pits were numerous and irregularly shaped with a rough, cross-hatched structure. much fewer in number ellipsoidal crystallographically faceted surfaces. Higher Epit resulting from lower [Cl−] impeded initiation Cathodic resource competition likely limited growth resulted total...
Numerous studies on the corrosion response of metal AM have been conducted. Nonetheless, specimens being tested are commonly ground or polished to remove outer as-built surface. If is truly going be employed as a transformative technology that can produce complex shapes do not require traditional machining, then material needs evaluated in state. The reality alloys shown significant inconsistencies regarding surface texture, topology, and residual stress. One metric has unpredictability...
Corrosion is an issue in Mg alloys resulting from chemical, and hence electrochemical, heterogeneity of alloy microstructures. In AZ31B-H24 (UNS M11311), Al8Mn5 intermetallic particles are dispersed throughout the matrix, forming microgalvanic couples. Laser surface modification was performed Ar N2 environments with a pulsed excimer laser (λ = 248 nm, 25 ns full width at half maximum) aim imparting chemical homogeneity on corrosion resistance. The results show can be partially or completely...
Corrosion protection of Mg and its alloys remains a challenge hindering widespread application. The propensity for alloy AZ31B-H24 (Mg-3Al-1Zn) to be protected via sacrificial anodic based cathodic was evaluated. Potentiostatic polarization in 0.6 M NaCl 0.1 M MgCl2 revealed that wide range potentials practical or kinetic-based is possible but substantial TRIS not observed. In addition, residual corrosion rates at their open-circuit potential were greater than expectations from...
Poor intrinsic corrosion resistance of Mg alloys is often attributed to recommended heterogeneous microstructures containing more electrochemically noble secondary phases resulting in the preferential dissolution Mg. The investigation herein demonstrates laser (excimer laser, λ = 248 nm, 25 ns) processing cast Mg-Al-Zn (AZ91D) and Mg-Al (AM60B) mitigates impact β-Mg17Al12 Al-Mn intermetallic particles have on resistance. Control fluence reduced surface defects commonly formed while improving...
Abstract Understanding the mechanistic relationship between environment, microstructure, and local kinetics of atmospheric corrosion damage remains a central challenge. To address this challenge, study used laboratory-based X-ray tomography to directly observe attack in-operando over an extended period, enabling insights into evolving growth morphology individual pits months exposure. Damage progression associated with nine in 99.9% pure aluminum wire exposed chloride salts humid air was...
Residual stress is a contributor to corrosion cracking (SCC) and common byproduct of additive manufacturing (AM). Here the relationship between residual SCC susceptibility in laser powder bed fusion AM 316L stainless steel was studied through immersion saturated boiling magnesium chloride per ASTM G36-94. The varied by changing sample height for as-built condition additionally heat treatments at 600°C, 800°C, 1,200°C control, some cases reduce, stress. In general, all samples showed with...
Exposure testing was performed on CoCrFeMnNi equiatomic high entropy alloy (HEA) produced via directed energy deposition additive manufacturing in NaNO 3 -KNO (60–40 wt%) molten salt at 500 °C for 50 h to evaluate the corrosion performance and oxide film chemistry of HEA. Potentiodynamic electrochemical testing, scanning electron microscopy, focused ion beam milling coupled with dispersive spectroscopy, Raman X-ray diffraction, photoelectron inductively plasma optical emission spectroscopy...