Innovative Process for Manufacturing Hydrogenated Titanium Powder for Solid State Production of P/M Titanium Alloy Components

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1 Innovative Process for Manufacturing Hydrogenated Titanium Powder for Solid State Production of P/M Titanium Alloy Components O.M. Ivasishin 1, M.V.Matviychuk 1, C.A.Lavender 2, G.I.Abakumov 3, V.A.Duz 3, V.S.Moxson 3 1-Institute for Metal Physics, Kiev, Ukraine 2-Pacific Northwest National Laboratory, Richland, WA, USA 3-ADMA Products, Inc. Hudson, OH, USA

2 Conventional Titanium Ingot Metallurgy Process High Cost, High Energy Consumption, High Labor, High Waste A high buy-to fly ratio process Ti Sponge Ingot Billet Slabs Mill Product Pre-forms Mill Product Finished Products Development of new technologies that provide costeffective manufacturing of titanium alloy components provides expanded application for titanium products.

3 Conventional Powder Metallurgy Powder production Atomization PREP HDH Blending Consolidation Sinter Finished Products No Significant Cost Reduction Through Conventional Powder Metallurgy Process

4 Issues that have Hindered Titanium Powder Metallurgy Industry Development 1. Chemistry issues: High Interstitial content the need to remove Chlorine, Magnesium, Sodium (with ingot metallurgy melting removes interstitials) High oxygen content (related to high surface area of titanium powders, with ingot metallurgy removed by melting) 2. Properties issues: Inferior Low Cycle Fatigue and fatigue related properties, inferior fracture toughness Weld-ability Issues P/M Ti alloys did not meet Airspace Material Specifications (AMS)

5 Global Powder Metallurgy Industry (Annual - All metals) $25 Billion (Global) $5 Billion (USA) Over 70% to Auto Industry Source: Metal Powder Industries Federation June 2010

6 Cooperation(started late 1990 s) Aimed at development of most cost-effective BEPM press-and-sinter approach for manufacturing titanium components possessing relative density 98-99%, chemical and microstructural homogeneity and mechanical properties to meet commercial demands. U K R A I N E TITANIUM INSTITUTE INSTITUTE FOR METAL PHYSICS ZTMC leading organization in titanium R&D in FSU basic studies in titanium alloy and process development, Ukrainian team leader one of the largest titanium sponge producer, world leader in hydrogenated titanium U S A R&D in low-cost titanium powder and components manufacturing processes for DOE applications Components producer, R&D

7 Titanium Powders Produced by electrolysis in 1990`s

8 One of the largest titanium sponge producers and world leader in hydrogenated titanium sponge.

9 High-Dense (99%) BEPM Titanium Alloys TiH 2 Ti, Alloying Elements Powders Powder Blend Blending Compaction Employment of TiH 2 instead of Ti powder in BEPM allows attainment of 99% density and mechanical properties equivalent to those of ingot materials with most cost-effective pressand-sinter approach (without HIP) BE Compact (NNS) Component HIP Sintering Low Porous Component Specific mechanism of compaction optimized green porosity Shear type phase transformation TiH 2 Ti ( or ) high density of crystal lattice defects Surface self reducing by atomic hydrogen Faster sintering, higher sintered density, lower impurity content

10 Relative density,% Relative density,% Comparison of Ti- and TiH 2 -based Blends TiH 2 -based blends Sintered densities of TiH 2 blends: Ti-based blends Molding pressure, MPa 99% Ti-6Al-4V alloy do not noticeably depend on molding pressure - higher than in equivalent Ti-based blends. 99% Molding pressure, MPa

11 Development of cost-effective technology for manufacturing hydrogenated titanium Integrated process MgCl 2 TiCl 4 Vacuum Argon Hydrogen Ti sponge block (Kroll process) Hydrogenated Ti sponge block (modified Kroll process) Reduction (retort 1m) Partial vacuum separation of titanium sponge. Cooling Hydrogenation Hydrogenated powder Hydrogenated Ti sponge block crushing

12 Production of Hydrogenated Titanium Powders Requirements: - Industrial scale - large quantity of powder - Desirable chemistry (hydrogen and impurity content) - Sizing - Affordability

13 Typical Characteristics of Hydrogenated Titanium Cl Fe Ni C N O H Hydrogenated Ti Sponge (ZTMC) Powder (ADMA) TiH 2 sponge TiH 2 powder (-100 mesh)

14 Hydrogenated Ti sponge block (modified Kroll process) vs Ti sponge block (Kroll process) easier crushing Cost reduction underseparated Cost increasing hydrogenation shorter time lower energy lower labor Cost of Hydrogenated Powder Cost of Titanium Sponge

15 Components Manufacturing Developed by ADMA ADMA Titanium P/ M in house Processes Post-Processing Outside vendors Forging Die Press Finished product Rolling Flat (foil, sheet, plate) Round (bar, rod) TiH 2 + Master Alloy Powder Direct Powder Rolling Vacuum Sintering Extrusion Flowform Cold Isostatic Pressing Vacuum Sintering HIP

16 Alloy Synthesis Strategy Developed by IMP Chemical and microstructural homogenization Healing of pores Optimized condition: -chemical (microstructure) homogeneity - low volume fraction, spherical shape and minimized size of pores - fine beta grains - low impurity content L av Rav L av -average grain size R av -average pore size -porosity Grain growth (depends on volume fraction, size and morphology of pores ) Synthesis temperature and time

17 Diffusion of Alloying Elements in Temperature, o C Titanium D, m 2 sec -1 - Diffusion determines chemical homogenization and sintering of powders - Peculiarities of alloy synthesis depends on its composition

18 Expansion (mm/mm) Temperature ( o C) Dilatometry Indication that Dilatometry impurities Data and for alloying ITP and elements DuPont Powders affect powder metallurgy processing (Tests ran an Argon Atmosphere with Flowrate of 2000 sccm) D ITP-LP ITP R1-U2.2 ITP Ti-V Temp and Time High Refined TiCl 4 CP Low Cost TiCl 4 CP Highly Refine TiCl 4 TiV Time (minutes) 0

19 Anomalous Grain Growth Euler Map =200 µm; Subgrains; Step=4.3 µm; Grid265x613 =200 µm; E1-3; Step=4.3 µm; Grid265x613

20 Example of Alloys Sintered from Hydrogenated Titanium Powder Alloy Density, % YS, MPa UTS, MPa El., % RA, % Ti-6Al-4V ASM specification Ti-5Al-5V-5Mo-3Cr BMS Specification. High strength condition Ti-10V-2Fe-3Al AMS 4984 Specification. High strength condition Gas impurities: Oxygen: %, Hydrogen %

21 Inherent Issues Related to -hydrogen -oxygen -chlorine -master alloy powders

22 Hydrogen 1 kg TiH 2 40 g or 448 liters of H 2 - high capacity pumping system required - heating rate/hydrogen pressure control is necessary for proper processing

23 Oxygen -Excessive oxygen content in synthesized alloys leads to increased strength but low ductility or even brittleness Sources of contamination: -starting base powder (typically wt.%), -alloying powders (up to 1 wt.%), -processing (blending, compaction, sintering procedures) Hydrogenated powder Green compact Ti-6Al-4V Ti-6Al-4V alloy 0.15 wt.% 0.26 wt.% 0.11 wt.% final oxygen content is generally lower than in green compacts due to hydrogen s reducing effect

24 Low-oxygen P/M Ti-6Al-4V Billets from Hydrogenated Ti Powder Ti-6Al-4V billet 8.50 x 12.0 x lbs

25 Chlorine Starting chlorine content 0.10% in sponge reduced to 0.08% during sponge hydrogenation and further during sintering providing sufficient mechanical properties Ti-6Al-4V Final alloy: Cl: 0.015% O: 0.112% N: 0.024% YS, MPa UTS, MPa El., % RA, %

26 Master Alloy Powders MA/titanium matrix interface affects shrinkage MA particle size distribution affects residual porosity Ti 1023 MA

27 Conclusion Cooperation proved successful in the development of a new titanium powder metallurgy process. More details as to the results under the hydrogenated titanium powder process will be presented by our next speaker.