PowerPoint Presentation

[Audio] Role of Carrier Gas on Microstructure and Anisotropic Properties of Cold-sprayed Scalmalloy Deposits Anil Lama Denny John, Tanaji Paul, Arvind Agarwal Cold Spray and Rapid Deposition Laboratory (ColRAD) Department of Mechanical and Materials Engineering Florida International University [email protected] | 786-818-9502 1.

[Audio] The need for high-strength Aluminum alloy Replacing Al alloys by other high-strength materials Al alloys - light weight - high strength-to-weight ratio; structural applications Cost ineffectiveness Al7075 (maximum reported UTS: 540 MPa) Limited strength-to-weight ratio Source: daytonaero.com Replacing Al alloy pylon rib by Ti alloy Cost 3x Need of Cold-sprayed Al alloy > Al7075 Maximum reported UTS of cold-sprayed Aluminum alloys Wen Wang et al., JMRT 9(2020),p9073 B.C. White et al., Fatigue 112(2018),p355 M.R.Rokni et al., JTST,27(2018),p818 M.R.Rokni et al., S&CT,309(2017),p641 M.R.Rokni et al., S&CT,310(2017),p278 2.

[Audio] Scalmalloy as a potential high-strength Al alloy Use high-strength Al alloy as starting powder Scalmalloy (Al-Mg-Sc-Zr alloy) can surpass commercial Al alloys in laser-based AM Limited strength of commercially Tailor strength by post-processing available Al alloy Strengthening mechanism in Scalmalloy Method of fabrication PBF PBF + Postprocessed Feedstock Al-4.4Mg-1.73Sc-0.3Zr-0.4Mn (wt.%) Precipitation/ Dispersoid strengthener Max reported σy (MPa) 306.5 540.2 L12 Structure Al atoms Sc/Zr atoms Max reported σu (MPa) 334.5 541.3 Grain refiner F. Lasagni et al., Prog. Addit. Manuf. 7(2022), p29-29 Nano-size thermally stable precipitates 3.

[Audio] 1. 2. Deposits Cold Spray Deposition of Scalmalloy N2-deposit He-deposit Gas atomized Scalmalloy 5 mm deposit thickness Al-4.6Mg-0.72Sc-0.3Zr-0.5Mn (wt. %) 5 mm substrate substrate BD 10 µm 5 mm d1 d2 FR Porosity 50 µm d2 N2-deposit 2.43 ± 0.45 1.2 ± 0.5 Flattening Ratio (FR) = He-deposit 2.67 ± 0.53 0.12 ± 0.03 d1 4.

[Audio] Cold Spray Deposition of Scalmalloy BD Bimodal microstructure Ultra-fine grains Micron-sized grains Jetting region (Splat interior) 10 µm 10 µm Pronounced deformation in He-deposit 111 IPF-Z 10 µm 10 µm 101 001 5 He-deposit N2-deposit.

[Audio] Estimation of dislocation density by XRD measurement Particle velocity during deposition: ?? vp = particle velocity ?? = ????? vg = velocity of gas ? + ?. ?? ? ? ?? D = mean diameter of particle L= length of diverging section of nozzle ρg = characteristics strain Po = gas pressure Vp(m/s) Dislocation density, x 1013 (1/m2) Powder 0.16 N2-deposit 1096 1.94 He-deposit 1485 6.98 higher dislocation density in He-deposit Higher particle velocity Increased deformation 6.

[Audio] Nanoscale length mechanical properties of the deposits BD Region of interest Splat interior Jetting region Test condition 10 µm Load controlled : 5 mN max load Berkovich tip 10 x 8 array of indents Splat interior Nanohardness (GPa) Location N2-deposit He-deposit Splat interior 1.20 ± 0.20 1.21 ± 0.16 Jetting region 0.99 ± 0.11 1.00 ± 0.06 111 Jetting region Deformation of 1 to few grains 5 µm 7 001 101.

[Audio] Microhardness measurement along deposit thickness Test condition 200 gmF load, 15 sec dwell time Vickers tip A series of indents 20 µm Deformation involves few splats HV0.2 N2-deposit 136 ± 6 He-deposit 149 ± 6 8.

[Audio] Plastometry-based Indentation Profilometer (PIP): Background 1. 2. 1. Indentation with predefined load/displacement 2. Residual indent profile measurement 3. Iterative finite element simulation to fit the indented profile using Voce hardening parameters 4. Conversion of true strain-stress from FEM simulation to nominal stressr (µm) strain curve 3. 4. Voce Plasticity equation ? = ?? − ?? − ?? ??? ? ?? ? = true stress ?? = yield stress ?? = saturation stress ?? = true strain ? = characteristics strain 9.

[Audio] Strength comparison of cold-sprayed Al alloys with Scalmalloy Our Study Literature Indentation surface BD (Tensile test) N2-deposit He-deposit σy (MPa) σU (MPa) El (%) Maximum reported Ultimate Tensile Strength for as-deposited Al alloys at room temperature. N2-deposit 325 ± 16 450 ± 6 16 ± 1 He-deposit 378 ± 8 467 ± 1 13 ± 1 He-deposit > as-deposited 6061 by 18 % N2-deposit > as-deposited 6061 by 14 % Dislocations ∆?? = ???? ? Strengthening by ∆??= ?? + ? Grain refinement 10 ? Δσp = increase in strength by work hardening α = numerical factor (0.33) M = Taylor factor G= Shear modulus b = burgers constant ρ = density d = average grain diameter ΔσY = increase in strength by grain refinement.

[Audio] PIP indent morphologies on top surface of the deposits BD BD Indentation surface BD 1.0 0.5 0.0 in mm - 0.5 500 µm - 1.0 0.0 0.5 1.0 - 0.5 - 1.0 20 µm in mm BD 1.0 0.5 Y Loading direction 0.0 in mm X - 0.5 Splat 500 µm - 1.0 0.0 0.5 1.0 - 0.5 - 1.0 in mm - 40 - 20 0 - 60 - 80 in µm 10 11 Circular indent morphology and uniform pile-up distribution quasi-circular splats, showing in-plane isotropy..

[Audio] In-plane anisotropy captured by PIP 0.5 9 BD Y BD ~8 µm ~ 8 µm 10 468 µm 0 0 0.25 ~ 6 µm ~ 6 µm - 10 -10 -20 0.0 - 20 484 µm in mm X -30 Indentation surface -40 - 0.25 - 30 - 46 µm Displacement (µm) -50 200 µm - 40 - 0.5 r (mm) in µm 0.0 0.25 0.5 - 0.25 - 0.5 in mm Y Pile-up height Pile-up spread Loading direction X (µm) Indent depth (µm) x y (µm) (µm) N2-deposit 6 3 450 49 d1 Splat He-deposit 8 6 370 46 d2 Flattened indent morphology contributed to in-plane anisotropy Hall-Petch relation: ?? = ?? + ? 20 µm ? 12.

[Audio] Through thickness PIP-inferred properties BD 500 µm Hedeposit N2deposit No variation of mechanical properties along the thickness 13.

[Audio] Conclusions Sprayability of novel Scalmalloy by Cold Spraying to achieve 5 mm thickness Our Study Literature (Tensile test) Higher degree of splat flattening with limited porosity in Hedeposit, attributing to higher particle impact velocity Increased dislocation density and grain refinement contributed to hardness enhancement in He-deposit by ~ 10% and increase in YS by ~ 16% and UTS by ~ 6% N2-deposit He-deposit UTS: He-deposit > as-deposited 6061 by 18% & N2deposit > as-deposited 6061 by 14 % Future work Tensile testing of deposits Maximum reported UTS for as-deposited Al alloys Post-heat treatment to further enhance the strength of the deposits. 14.

[Audio] Acknowledgement 15. Acknowledgement 15.