SEARCH · Engineering Papers
Results for “powders”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Solute and phase heterogeneous distribution at different scales and its effect on ageing physical phenomena in a laser powder bed fusion produced maraging steel
Not Available
Process-structure relationships in laser directed energy deposition of molybdenum powder within a Ti–6Al–4V matrix
Not Available
A mechanistic study on environment gas in laser powder bed fusion
A variety of protective or reactive environmental gases have recently gained growing attention in laser-based metal additive manufacturing (AM) technologies due to their unique thermophysical properties and the potential improvements they can bring to the build processes. However, much remains unclear regarding the effects of different gas environments on critical phenomena in laser AM, such as rapid cooling, energy coupling, and defect generation. Through simultaneous high-speed synchrotron x-ray imaging and thermal imaging, we identify distinct effects of two environmental gases in laser AM and gained a deeper understanding of the underlying mechanisms. Compared to the commonly used protective gas, argon, it is found that helium has a negligible effect on cooling the part. However, helium can suppress unstable keyholes by decreasing effective energy absorption, thus mitigating keyhole porosity generation and reducing pore size under certain processing conditions. In conclusion, these observations provide guidelines for the strategic use of environmental gases in laser AM to produce parts with improved quality.
Surface modification of organic powders for enhanced rheology via atomic layer deposition
Not Available
Acid-base synthesis of aluminum iodate hexahydrate powder as a promising propellant oxidizer
In this study, an acid-base precipitation reaction is detailed to synthesize pure crystals of the oxidizer rich compound [Al(H 2 O) 6 ](IO 3 ) 3 (HIO 3 ) 2 and described here for the first time. The molecule is called aluminum iodate hexahydrate (AIH) and characterized for its energetic potential as an oxidizer in propellant applications. The synthesis method produced bipyramidal hexagonal crystals that are characterized physically and chemically by microscopy, pycnometry, and X-ray crystallography. Further energetic characterization is performed by bomb calorimetry, and impact, friction, and electrostatic discharge ignition sensitivity. This study introduces the potential of AIH as an alternative solid propellant by comparison to the properties of ammonium perchlorate (AP) and ammonium nitrate (AN).
Predictive microstructure distribution and printability maps in laser powder bed fusion for a Ni–Cu alloy
Not Available
Microstructure prediction for Ti-22Al-25Nb in laser powder bed fusion
This work presents a physics-informed framework for predicting solidification morphology and defect susceptibility in additively manufactured Ti–22Al–25Nb across a broad processing space. The framework integrates solidification microstructure selection (SMS) analysis with a single-track defect-based printability map to establish a unified methodology linking processing parameters to both interfacial morphology and manufacturability. Thermal gradients G and solidification rates R are first computed using the Thermo-Calc Additive Manufacturing (TC-AM) module, a finite-interface-dissipation (FID) phase-field (PF) model coupled with CALPHAD method is then employed to systematically distinguish planar and dendritic regimes as functions of $G$ and $R$. By superimposing the printability map onto the morphology projections, a comprehensive process–structure framework is obtained. Across most processing conditions, the predicted microstructure is predominantly dendritic, while planar growth emerges only under selected laser power $P$ and scan speed $v$ combinations. In addition to morphology classification, the framework quantifies the dendritic area fraction and introduces a width-based morphology descriptor to characterize the spatial extent of planar/dendritic regions within the melt pool. It provides mechanistic insight into the interplay between solidification physics and defect formation, offering practical guidance for parameter selection and microstructural control in Ti–22Al–25Nb additive manufacturing (AM).
Atomic-structure, microstructure and mechanical properties of glass powder modified metakaolin-based geopolymer
Abstract not provided
Cementitious activity optimization studies of iron tailings powder as a concrete admixture
Not Available
Inter-melt pool corrosion and repassivation of SS316L stainless steel processed by laser powder bed fusion
Not Available
Efficacy and safety of yinqiao powder combined with western medicine in the treatment of pneumonia: A systematic review and meta-analysis
Not Available
Resolution and geometric limitations in laser powder bed fusion additively manufactured GRCop-84 structures for a lower hybrid current drive launcher
Not Available
Near-threshold fatigue crack growth in laser powder bed fusion produced alloy 718
Not Available
Crack growth in laser powder bed fusion fabricated alloy 718 at 650 °C under static and cyclic loading
Not Available