scholarly journals On the Influence of Alloy Composition on the Additive Manufacturability of Ni-Based Superalloys

2022 ◽  
Author(s):  
Joseph N. Ghoussoub ◽  
Yuanbo T. Tang ◽  
William J. B. Dick-Cleland ◽  
André A. N. Németh ◽  
Yilun Gong ◽  
...  
Keyword(s):  
Solid State ◽  
Stress Relaxation ◽  
Crack Formation ◽  
Alloy Composition ◽  
Relaxation Effect ◽  
Scanning Calorimetry ◽  
Powder Bed ◽  
Creep Stress ◽  
Solidification Cracks

AbstractThe susceptibility of nickel-based superalloys to processing-induced crack formation during laser powder-bed additive manufacturing is studied. Twelve different alloys—some of existing (heritage) type but also other newly-designed ones—are considered. A strong inter-dependence of alloy composition and processability is demonstrated. Stereological procedures are developed to enable the two dominant defect types found—solidification cracks and solid-state ductility dip cracks—to be distinguished and quantified. Differential scanning calorimetry, creep stress relaxation tests at 1000 °C and measurements of tensile ductility at 800 °C are used to interpret the effects of alloy composition. A model for solid-state cracking is proposed, based on an incapacity to relax the thermal stress arising from constrained differential thermal contraction; its development is supported by experimental measurements using a constrained bar cooling test. A modified solidification cracking criterion is proposed based upon solidification range but including also a contribution from the stress relaxation effect. This work provides fundamental insights into the role of composition on the additive manufacturability of these materials.

scholarly journals Understanding solid-state processing of pharmaceutical cocrystals via milling: Role of tablet excipients

2021 ◽  
Vol 601 ◽  
pp. 120514 ◽  
Author(s):  
Rahamatullah Shaikh ◽  
Saeed Shirazian ◽  
Sarah Guerin ◽  
Eoin Sheehan ◽  
Damien Thompson ◽  
...  
Keyword(s):  
Solid State ◽  
Pharmaceutical Cocrystals ◽  
Tablet Excipients ◽  
State Processing

scholarly journals Effect of tungsten disulfide nanotubes on crystallization of polylactide under uniaxial deformation and annealing

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Fausta Loffredo ◽  
Loredana Tammaro ◽  
Tiziana Di Luccio ◽  
Carmela Borriello ◽  
Fulvia Villani ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Structural Evolution ◽  
Tungsten Disulfide ◽  
Fine Tuning ◽  
Nanocomposite Films ◽  
Uniaxial Deformation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering

AbstractTungsten disulfide (WS2) nanotubes (NTs) are examined here as a filler for polylactide (PLA) for their ability to accelerate PLA crystallization and for their promising biocompatibility in relevant to biomedical applications of PLA-WS2 nanocomposites. In this work, we have studied the structural and thermal properties of PLA-WS2 nanocomposite films varying the concentration of WS2 NTs from 0 (neat PLA) to 0.6 wt%. The films were uniaxially drawn at 90 °C and annealed at the same temperature for 3 and 10 min. Using wide angle x-ray scattering, Raman spectroscopy and differential scanning calorimetry, we probed the effects of WS2 NT addition on the structure of the PLA films at various stages of processing (unstretched, stretching, annealing). We found that 0.6 wt% of WS2 induces the same level of crystallinity in as stretched PLA-WS2 as annealing in neat PLA for 10 min. These data provide useful insights into the role of WS2 NTs on the structural evolution of PLA-WS2 composites under uniaxial deformation, and extend their applicability to situations where fine tuning of PLA crystallinity is desirable.

scholarly journals Role of laser powder bed fusion process parameters in crystallographic texture of additive manufactured Nb-48Ti alloy

2021 ◽  
Author(s):  
Rafael de Moura Nobre ◽  
Willy Ank de Morais ◽  
Matheus Tavares Vasques ◽  
Jhoan Guzmán ◽  
Daniel Luiz Rodrigues Junior ◽  
...  
Keyword(s):  
Process Parameters ◽  
Crystallographic Texture ◽  
Fusion Process ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Powder Bed

scholarly journals Laser Powder Bed Fusion Processing of Fe-Mn-Al-Ni Shape Memory Alloy—On the Effect of Elevated Platform Temperatures

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 185
Author(s):  
Felix Clemens Ewald ◽  
Florian Brenne ◽  
Tobias Gustmann ◽  
Malte Vollmer ◽  
Philipp Krooß ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Crack Formation ◽  
Microstructural Analysis ◽  
Tensile Load ◽  
Grain Structure ◽  
Powder Bed Fusion ◽  
Laser Powder Bed Fusion ◽  
Cyclic Heat Treatment ◽  
Powder Bed ◽  
Cyclic Heat

In order to overcome constraints related to crack formation during additive processing (laser powder bed fusion, L-BPF) of Fe-Mn-Al-Ni, the potential of high-temperature L-PBF processing was investigated in the present study. The effect of the process parameters on crack formation, grain structure, and phase distribution in the as-built condition, as well as in the course of cyclic heat treatment was examined by microstructural analysis. Optimized processing parameters were applied to fabricate cylindrical samples featuring a crack-free and columnar grained microstructure. In the course of cyclic heat treatment, abnormal grain growth (AGG) sets in, eventually promoting the evolution of a bamboo like microstructure. Testing under tensile load revealed a well-defined stress plateau and reversible strains of up to 4%.

The Role of Protons and Formation Cu(NH3)2+ During Ammonia-Assisted Solid-State Ion Exchange of Copper(I) Oxide into Zeolites

2018 ◽  
Vol 62 (1-4) ◽  
pp. 100-107 ◽  
Author(s):  
Peter N. R. Vennestrøm ◽  
Lars F. Lundegaard ◽  
Christoffer Tyrsted ◽  
Dmitriy A. Bokarev ◽  
Alina I. Mytareva ◽  
...  
Keyword(s):  
Solid State ◽  
Ion Exchange

Role of solid-state structure in propene hydrogenation with nickel catalysts

1990 ◽  
Vol 86 (4) ◽  
pp. 739 ◽  
Author(s):  
Giovanni Carturan ◽  
Stefano Enzo ◽  
Renzo Ganzerla ◽  
Maurizio Lenarda ◽  
Roberto Zanoni
Keyword(s):  
Solid State ◽  
Nickel Catalysts ◽  
State Structure ◽  
Solid State Structure
Sign in / Sign up

Export Citation Format

Share Document