Overview of Materials Used in Additive Manufacturing

Transcription

1 Overview of Materials Used in Additive Manufacturing D.L. Bourell Temple Foundation Professor The University of Texas at Austin NSF Workshop: Environmental Implications of Additive Manufacturing Arlington VA October 14, 2014

2 Material Demands for AM Form Proper Feedstock Fabricator Processability Post-Processability as Needed Acceptable Service Properties

3 Material for Additive Manufacturing SL LS, FDM SLM, EBM, DED Roadmap for Additive Manufacturing: Identifying the Future of Freeform Processing, D.L. Bourell, M.C. Leu, D.W. Rosen, eds, The University of Texas at Austin, 2009, 92 pages.

4 Material for Additive Manufacturing Composites Binders Transient Permanent Support Structures Graded Structures Multi-Materials Roadmap for Additive Manufacturing: Identifying the Future of Freeform Processing, D.L. Bourell, M.C. Leu, D.W. Rosen, eds, The University of Texas at Austin, 2009, 92 pages.

5 Materials Grand Challenge in AM Quality Process Consistency, Repeatability Reliability Wide Diversity of Compositions Superior Structure and Properties Low (Feedstock and Processing) Cost

6 Materials for Fused Deposition Modeling (Amorphous Thermoplastics) ABS [Acryonitrile Butadiene Styrene] $7-115/lb Polycarbonate PC/ABS Blend PLA [Polylactic Acid] $113/lb $7-25/lb Polyetherimide (PEI) [Stratasys ULTEM] $220/lb Nylon Co-Polymer (new in 2012) Source: 2012 Wohlers Report

7 Materials for Stereolithography and Material Jetting (Proprietary Thermosets, ~$100/lb) Acrylics Acrylates Epoxies ABS-like (Material Jetting) Source: 2012 Wohlers Report

8 Materials for Laser Sintering (Crystalline/Semi-Crystalline Thermoplastics) Polyamide (Nylon) 11 and 12 Neat Glass Filled Carbon Filled Metal (Al) Filled Polystyrene (Lost Wax Patterns) Polypropylene Polyester ( Flex ) Polyetheretherkeytone (PEEK) Thermoplastic Polyurethane (new in 2012) Nylon 6 (new in 2012) ~$40/lb ~$200/lb Source: 2012 Wohlers Report

9 Metals for AM (BJ, DED, PBF, SL) Tool Steel ~$50/lb Stainless Steel ~$50/lb Aluminum Alloys ~$50/lb Co-Cr Alloys ~$55-250/lb Nickel Alloys ~$95-125/lb CP Titanium ~$ /lb Ti-6Al-4V ~$ /lb Gold Silver Most Popular: SLM EBM BJ (ExOne) DED (LENS, POM, etc.) LOM (UAM) Source: 2012 Wohlers Report

10 AM Materials/Properties Summary Property AM Parts Compared to Conventional Processing Stiffness Equal Strength As Strong or Stronger Hardness Harder or as Hard Ductility Less Ductile Fatigue (Cyclic) Weaker Toughness Less Tough Post-processing to remove porosity (e.g., hot isostatic pressing) restores all properties if the interfaces are properly destroyed

11 Summary of AM Mechanical Behavior Modulus of Elasticity Metals Polymers Non-Metallics Porosity Driven (Power Law) Porosity Driven (Power Law) Porosity Driven Strength/Ductility Porosity Driven Isotropic (High ) Porosity Driven Anisotropic (Ductility) Porosity Driven Weibull Mod. Fatigue σ e <0.5UTS or no σ e - Fracture Toughness Less or equal to bulk - ρ = = 1 ρ th ε

12 Processing Effects on Porosity in SLM Processed 17-4 Stainless Steel Power = 190 W V scan = 1.30 m/s T layer = 50 µm Power = 190 W V scan = 0.80 m/s T layer = 30 µm A.B. Spierings, K. Wegener, G. Levy, Designing Material Properties Locally with Additive Manufacturing Technology SLM, Proc. SFF Symposium (2012), pp

13 Examples of Porosity in EBM Ti-6Al-4V Khalid Rafi, H., Karthik N.V., Thomas L. Starr, Brent E. Stucker, Defect formation in EBM parts built in horizontal orientation, Proc. SFF Symposium (2012), pp

14 Modulus of Elasticity 600 Nylon 12 Stiffness (ksi) C.E. Majewski and N. Hopkinson, Effect of section thickness and build orientation on tensile properties and material characteristics of Laser Sintered nylon-12 parts, SFF Symposium Proceedings, Univ. Texas at Austin, 2010, pp

15 Strength 316L Stainless Steel SLM, As Processed ksi 27.5 ksi J.P. Kruth, et al., Binding Mechanisms in Selective Laser Sintering and Selective Laser Melting, SFF Symposium Proceedings, Univ. Texas at Austin, 2004, pp

16 Strength and Ductility 66Co-28Cr-6Mo EBM, HIP, Homogenized (ksi) (ksi) R.S. Keicher, A.M. Christiansen and K.W. Wurth, Electron Beam Melted (EBM) Co-Cr-Mo Alloy for Orthopaedic Implant Applications, SFF Symposium Proceedings, Univ. Texas at Austin, 2009, pp

17 Mechanical Behavior of LS Nylon LS Bulk* Yield (MPa) Tensile (MPa) % Elongation *CES Edupack Matl Selector, Version 7.0.0, Granta Ltd., 2011 D.K. Leigh, Harvest Technologies, priv. comm., 2011.

18 Strength Log(H) SLM Maraging Steel 18Ni300 Various Layer Thicknesses R.M. German, Powder Metallurgy and Particulate Materials Processing, MPIF, Princeton NJ, 2005, p Log( ) E. Yasa, et al., Microstructure and Mechanical Properties of Maraging Steel 300 after Selective Laser Melting, SFF Symp., 2010, pp

19 Strength Room-Temperature Tensile Strength of Pre-Mixed SLS (90Cu-10Sn) Bronze and Commercially Pure Nickel Powder as a Function of Relative Density = 1-ε. (a) As SLS Processed, (b) SLS Processed and Sintered at C for 1 to 10 hr. M.K. Agarwala, D.L. Bourell, B. Wu, J.J. Beaman, An Evaluation of the Mechanical Behavior of Bronze-Ni Composites Produced by Selective Laser Sintering, SFF Symposium Proceedings, H.L. Marcus, J.J. Beaman, J.W. Barlow, D.L. Bourell and R.H. Crawford, eds., Austin TX, (1993).

20 Mechanical Properties of AM Parts Ductility Ductility( ε 0) Ductility( ε = 0) = ( 1 ε ) 3/ 2 ( 2 1+ Cε ) 1/ 2 Relative Ductility as a Function of Fractional Porosity for Pure Iron. Various Particle Sizes and Purity. [From Haynes, Powder Met., 1977, 20, 17-20]

21 Ductility LS Polyamide 12 C = R. Haynes, A Study of the Effect of Porosity Content on the Ductility of Sintered Metals, Powder Metallurgy 20 (1977) pp Elongation Relative Porosity ε D.K. Leigh, D.L. Bourell, J.J. Beaman, Basis for Decreased Mechanical Properties of Polyamide in Selective Laser Sintering Proc. SFF Symposium, Austin TX, 2011.

22 SLM Ti-6Al-4V Based on Post-Process Anneals (Furnace Cooled) Thöne, M., S. Leuders, A. Riemer, T. Tröster, H.A. Richard, Influence of heat-treatment on Selective Laser Melting products e.g. Ti6Al4V, Solid Freeform Fabrication Proceedings, (2012), pp

23 Fatigue Fatigue of FDM Processed ABS polymer Reid, Fatigue of Fused Deposition Modeled (FDM) Acrylonitrile Butadiene Styrene (ABS) Stage Three individual Project MEC 3098, Newcastle University School of Mechanical and Systems Engineering 2011.

24 Fatigue LENS Processed Ti-6Al-4V, Stress Relieved or HIPped P.A. Kobryn and S.L. Semiatin, Mechanical Properties of Laser-Deposited Ti-6Al-4V, SFF Symposium Proceedings, Univ. Texas at Austin, 2001, pp

25 Fracture Toughness LENS Processed Ti-6Al-4V, Stress Relieved or HIPped P.A. Kobryn and S.L. Semiatin, Mechanical Properties of Laser-Deposited Ti-6Al-4V, SFF Symposium Proceedings, Univ. Texas at Austin, 2001, pp

26 Ceramics AM Processing S = eee σ σ f m Weibull Behavior Γ 1 + m m m Sc S s S = Probability of Survival σ = Applied Stress σ f = Average Fracture Stress Γ(x) = Gamma Function = s x 1 e s dd S c = Effective Surface Area of a Component S s = Effective Surface Area of the Test Specimen m = Weibull Modulus

27 Ceramics AM Processing S = eee σ σ f m Weibull Behavior Γ 1 + m m m Sc S s 1 S = eee + σ σ f m Γ 1 + m m m Sc S s LLLL 1 S = LL + σ σ f m Γ 1 + m m m Sc S s LLLL 1 S = m LL σ + [ m LL σ f + LL C ]

28 Weibull Plot and Modulus

29 Weibull Plot, Sintered Alumina Al 2 O 3 powder, 0.4 μm Freeform Extruded Freeze-dried Sintered at 1,550 C for 2 h S = 10% S = 50% Weibull Modulus = 5 S = 90% 150 MPa 300 MPa Tieshu Huang, Michael S. Mason, Xiyue Zhao, Gregory E. Hilmas, Ming C. Leu, (2009) "Aqueous-based freeze-form extrusion fabrication of alumina components", Rapid Prototyping Journal, Vol. 15 Iss: 2, pp.88 95

30 Weibull Plot, Sintered FDM Silicon Nitride Less than 1 micron Si 3 N 4 FDM Binder Burnout and non-disclosed HT sinter Vintage 1 Starting Control Vintage 2 After processing quality improvements to minimize large porosity R. Clancy, V. Jamalabad, P. Whalen, P. Bhargava, C. Dai, S. Rangarajan, S. Wu, S. Danforth, N. Langrana, A. Safari, Fused Deposition of Ceramics: Progress Towards a Robust and Controlled Process for Commercialization, Proc. SFF Symposium, 1997, Austin TX, pp

31 Weibull Modulus, LOM Silicon Carbide Don Klosterman, Richard Chartoff, Nora Osborne, George Graves, Automated Fabrication of Monolithic and Ceramic Matrix Composites via Laminated Object Manufacturing (LaM), Proc SFF Symposium, Austin TX, 1997, pp

32 Weibull Modulus EFF Alumino-Silicate/Fused Silica Qingbin Liu, Ming C. Leu,,Harish Jose, Von L. Richards, Study of Ceramic Slurries for Investment Casting with Ice Patterns, Proc SFF Symp, Austin TX, 2004, pp

33 Materials Forecast Materials will be demanded in a quantity to justify volume production with concomitant reduction in unit cost for the user. Material cost will drop. Lower cost will increase usage, engendering greater demand, Several mini-suppliers or niche product companies have appeared in the last 5-10 years and seem to be surviving.

34 Materials Perspectives Common 3DP materials are generally not patent protected Material cost is high for consumers, but new suppliers do not seem to be entering the marketplace Perhaps the price will come down as material usage volume increases due to adoption My impression is that there is little consumer loyalty to a specific brand of material

35 Summary of AM Mechanical Behavior Mechanical behavior is predictable based on the traditional understanding of microstructure and processing. Porosity and inter-layer interfaces have a strong influence on the mechanical behavior. Anisotropy is not generally an issue if parts are built with low porosity and good layer interface. As processed parts are stronger than conventionally processed material but have lower elongation and poorer dynamic properties. Polymers produced using best practice have isotropic strength and anisotropic ductility.

36 Thank you