Novel Ultra-High Straining Process for Bulk Materials— Development of the Accumulative Roll-Bonding (ARB) Process Authored by Y. Saito, H. Utsunomiya, N. Tsuji, T. Sakai Presented by Chris Reeve September 13, 2004

Outline Introduction Model Design Application Experimental Procedure Results Conclusion Questions

Introduction Why is Accumulative Roll-Bonding important? Ultra-fine grain materials exhibit desirable properties High strength at ambient temperatures High-speed superplastic deformation at elevated temperatures High corrosion resistance Commonly accomplished by intense plastic straining

Introduction Processes used such as cyclic extrusion compression have two main drawbacks Requires large load capabilities, expensive dies Low production rate limits economic viability Function of paper is to introduce Accumulative Roll-Bonding (ARB) as a bulk manufacturing process

Introduction References: 1. Richert, J. and Richert, M., Aluminum, 1986, 62, Valiev, R. Z., Krasilnikov, N. A. and Tsenev, N. K., Mater. Sci. Engng, 1991, A137, Horita, Z., Smith, D. J., Furukawa, M., Nemoto, M., Valiev, R. Z. and Langdon, T. G., J. Mater. Res., 1996, 11, Saito, Y., Utsunomiya, H., Tsuji, N. and Sakai, T., Japanese Patent applied for. 5. Nicholas, M. G. and Milner, D. R., Br. Weld. J., 1961, 8, Helmi, A. and Alexander, J.M., J. Iron Steel Inst., 1968, 206, Metals Handbook, 9 th edn, Vol. 2. American Society for Metals, Metals Park, OH, 1979, pp Sakai, T., Saito, Y., Hirano, K. and Kato, K., Trans. ISIJ, 1988, 28, Saito, Y., Tsuji, N., Utsunomiya, H., Sakai, T. and Hong, R. G., Scripta mater., 1998, 39, Tylecote, R. F., The Solid Phase Welding of Metals. Edward Arnold, London, 1968.

Model Principle Rolling bond surfaces together Refines microstructure Improves properties. Iterative process Process design steps Surface treatment Stacking Roll bonding (heating) Cutting

Model Important parameters: t, t n, n, ε, r t For reduction of 50% in a pass Thickness after n cycles t = t 0 / 2 n Total reduction after n cycles r t = 1 – t / t 0 = 1 – 1 / 2 n Equivalent plastic strain

Design Application

Experimental Procedure No “special” equipment needed! Three alloys chosen Al 1100 (commercially pure) Al 5083 (Al-Mg alloy) Ti-added interstitial free (IF) steel Surfaces degreased, brushed Strips were heated 50 % reduction rolling under dry conditions

Experimental Procedure MaterialHeatingRoll Diameter (mm) Roll speed (m/min) Mean Strain Rate (/s) Al (1100)473 K x 5 min Al (5083)473 K x 5 min IF Steel773 K x 5 min

Results

Expected that grain refinement: Improves mechanical properties related to strength Decreased % elongation in direction of roll- bonding The number of cycles required to obtain peak strength can only be determined experimentally

Results Material# CyclesTS (MPa)% Elongation Al (1100)0 (Initial)8442 Al (1100)83048 Al-Mg (5083)0 (Initial)31925 Al-Mg (5083)75516 IF Steel0 (Initial)27457 IF Steel57516

Conclusions Practical industrial use for high strength structural applications Advances rolling technology by application to a specific materials processing method Industries most impacted: construction, marine, aerospace, automotive

Questions???