Enhanced mechanical properties of pure aluminium: Experimental investigation of effects of different parameters

Abstract

In current research, the interactive effects of different parameters such as melt overheating temperature, the location of gating system and incorporation of the grain refiner in bar and micro-powder form on the mechanical and structural characteristics of commercially pure aluminium are examined. Results show that increasing the melt temperature as well as employing a gating system with higher heat transfer rate increases the ultimate tensile strength (UTS) of the pure aluminium by 7%. Also, the introduction of 2wt% Al–5Ti–1B grain refiner in bar form into the overheated melt enhances the UTS values by two times, while incorporating 2wt% Al–5Ti–1B grain refiner in micro-powder form leads to achieving 32% higher UTS compared to the samples with grain refiner in the bar form due to the elimination of Al₃Ti brittle phase, as confirmed by XRD patterns and SEM fracture surface images.

Keywords

casting / grain refinement / tensile strength / microstructure / Al–5Ti–1B

References

[1] CarleD, BlountG. The suitability of aluminium as an alternative material for car bodies [J]. Materials & Design, 1999, 20(5): 267-272

[2] YücelB. An improved practice to manufacture Al–Ti–B master alloys by reacting halide salts with molten aluminium [J]. Journal of Alloys and Compounds, 2006, 420(12): 71-76

[3] MurtyB, KoriS, ChakrabortyM. Grain refinement of aluminium and its alloys by heterogeneous nucleation and alloying [J]. International Materials Reviews, 2002, 47(1): 3-29

[4] EskinD, KatgermanL. Effects of process parameters on the characteristics of the billet sump and related defect formation during DC casting of aluminum alloys [C]. Continuous Casting: Proceedings of the International Conference on Continuous Casting of Non-Ferrous Metals, 2006271276

[5] EskinD, SavranV, KatgermanL. Effects of melt temperature and casting speed on the structure and defect formation during direct-chill casting of an Al–Cu alloy [J]. Metallurgical and Materials Transactions A, 2005, 36(7): 1965-1976

[6] ReeseJ M. Characterization of the flow in the molten metal sump during direct chill aluminum casting [J]. Metallurgical and Materials Transactions B, 1997, 28(3): 491-499

[7] YangL. The effect of casting temperature on the properties of squeeze cast aluminium and zinc alloys [J]. Journal of Materials Processing Technology, 2003, 140(1): 391-396

[8] LiP, NikitinV, KandalovaE, NikitinK. Effect of melt overheating, cooling and solidification rates on Al–16wt.% Si alloy structure [J]. Materials Science and Engineering A, 2002, 332(1): 371-374

[9] EastonM, StjohnD. A model of grain refinement incorporating alloy constitution and potency of heterogeneous nucleant particles [J]. Acta Materialia, 2001, 49(10): 1867-1878

[10] EastonM, StjohnD. Grain refinement of aluminum alloys: Part I. The nucleant and solute paradigms—A review of the literature [J]. Metallurgical and Materials Transactions A, 1999, 30(6): 1613-1623

[11] JohnssonM, BackerudL, SigworthG K. Study of the mechanism of grain refinement of aluminum after additions of Ti-and B-containing master alloys [J]. Metallurgical Transactions A, 1993, 24(2): 481-491

[12] MohantyP, GruzleskiJ. Mechanism of grain refinement in aluminium [J]. Acta Metallurgica et Materialia, 1995, 43(5): 2001-2012

[13] MasoumiM, HuH, HedjaziJ, BoutorabiM. Effect of gating design on mold filling [J]. Transactions of the American Foundry Society, 2005, 113: 185-196

[14] Balci, AgaogullariD, GökçeH, DumanI, ÖveçogluM L. Influence of TiB2 particle size on the microstructure and properties of Al matrix composites prepared via mechanical alloying and pressureless sintering [J]. Journal of Alloys and Compounds, 2014, 586: S78-S84

[15] SadeghianZ, LotfiB, EnayatiM, BeissP. Microstructural and mechanical evaluation of Al–TiB₂ nanostructured composite fabricated by mechanical alloying [J]. Journal of Alloys and Compounds, 2011, 509(29): 7758-7763

[16] TeeK L, LuL, LaiM. In situ processing of Al–TiB2 composite by the stir-casting technique [J]. Journal of Materials Processing Technology, 1999, 89: 513-519

[17] YoussefY, DashwoodR, LeeP. Investigation of the latent heat associated with the solidification of an Al–TiB₂ composite [J]. Materials Science and Engineering A, 2005, 391(1): 427-432

[18] PattnaikA B, DasS, JhaB B, PrasanthN. Effect of Al–5Ti–1B grain refiner on the microstructure, mechanical properties and acoustic emission characteristics of Al5052 aluminium alloy [J]. Journal of Materials Research and Technology, 2015, 4(2): 171-179