“The Master Alloy of Al -Nb- B” 1
The Master Alloy of Al-Nb-B • Edmundo Burgos Cruz • Daniel Pallos Fridman • Alaércio Martins Vieira Technology Center - CBMM - Brazil
Overview • Motivation • Master Alloy Design • Production Process Development • Application as Grain Refiner • Future Al-Nb-B Master Alloy For the aluminium and automotive industries
Motivation The use of niobium as grain refining compound NbB 2 for Al-Si cast parts Joe Quinn, The Aluminum Association: “The auto opportunity: North American market trends” 7th Int. Aluminum Congress and ExpoAlumínio, São Paulo, Brazil, June 8 2016 Benefits: • Castability/Soundness of thin and complex parts Al-5Ti-B • Less porosity and hot tearing • Increase of mechanical properties/thoughness • Better homogeneity of properties • Potential weight savings of up to 30 % (Nb o ) with no loss of strength M. Nowak, L. Bolzoni , N. Hari Babu. Grain refinement of Al – Si alloys by Nb – B inoculation. Part I: Concept development and effect on binary alloys. Materials and Design 66 (2015) 366 – 375. BCAST
Brunel Al-Nb-B Master Alloy Development Materials: Reactions: • Nb metal powder (<45 um) • KBF 4 Challenges: Dissolution, yield and cost Al-1 wt% Nb M. Nowak, Refiner for aluminium-silicon alloys. PhD thesis BCAST, Brunel University, September. 2011. M. Nowak, L. Bolzoni , N. Hari Babu. Grain refinement of Al – Si alloys by Nb – B inoculation. Part I: Concept development and effect on binary alloys. Materials and Design 66 (2015) 366 – 375. BCAST 5
CBMM Alloy Design & Production Process 1° S High Nb alloy Nb(60-80%)-Al Niobium Metal (Nb o ) (Al 3 Nb) Al-(5%)Nb Master Alloy
CBMM Alloy Design & Production Process Nb x B y +Al 3 Nb 2º S NbAl (60-80%Nb) + AlB (4-8%B) = Al-5Nb-B 0.2-0.6% Al-5%Nb-0.6%B Master Alloy 3º S 5% 0.1% V.T. Witusiewicz et. al, “ The Al – B – Nb – Ti system. VI. Experimental studies and thermodynamic Grain Refined Al-Si Alloy modeling of the constituent Al – B – Nb system ” . Journal of Alloys and Compounds 587 (2014) 234 – 250.
Production Process Development Tapping Melting Down Nb-Al Addition Al-Nb-B Master Alloy Ingot
Master Alloy Characterization Chemical analysis (ICP) Main phases: • Al • Al 3 Nb Optical & SEM/EDS • AlB 2 • NbB 2 • Nb 2 B 3
Master Alloy Characterization Boron 20 um Al-Nb+B Aluminium Niobium Formation of nucleation sites: Al 3 Nb + AlB 2 = NbB 2 + 4 Al [1] 4 Al 3 Nb + 3 AlB 2 = 2 Nb 2 B 3 + 15 Al [2]
Application of Al-Nb-B as a grain refiner June 2015 e March 2016: Lab scale trials Al-Si Al-5Nb-B Master Alloy • Results: High grain refining of Al-Si alloys for Nb ≥ 0.05wt% • Decision: Validate the industrial application of the grain refiner
Application of Al-Nb-B as a grain refiner May 2016: 1 st Industrial validation trial & 0.1% Nb As Cast Reference Grain refining + Casting 0% Nb As Cast Grain refined Grain refined Al-Si ingots (0.1 %Nb) Result: High grain refining in as cast ingots
Application of Al-Nb-B as a grain refiner May 2016: 2 nd Industrial validation trial & Reference Remelted 0.1% Nb 0% Nb Grain refined Al-Si ingots As Cast Grain refined (0.1 %Nb) As Ingot remelting trials Cast Remelted Result: High grain refining after remelting
Application of Al-Nb-B as a grain refiner May & June 2016: 3 rd Industrial validation trials & 0.05%Nb 0.10%Nb 0.15%Nb 0% Nb High grain refining (from 3mm to < 0.3 mm) High porosity 0.15%Nb 0 %Nb 0.05%Nb 0.10%Nb 0.15%Nb No porosity
Future: Global CO 2 Emissions & Standards Automotive Ducker Worldwide: EAA Aluminium penetration in cars. Final Report. March 13, 2012. Public version
Future: Automotive Light Weight Desing 50 years of growth in the North American automotive market 180 kg 130 kg Castings (~70%) Joe Quinn, The Aluminum Association: “The auto opportunity: North American market trends” 7th International Aluminum Congress and ExpoAlumínio, São Paulo, Brazil, June 8 2016.
Future: Automotive Light Weight Design Niobium Microalloyed Steel + Niobium Grain Refined Aluminum Alloys for a sustainable world
Thank you!
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