Effect of Cr content and cooling rate on the primary phase of Al-2.5Mn alloy

Abstract

The effect of Cr content and cooling rate on the microstructure of Al-Mn alloy was studied using well resistance furnace melting, and the alloy was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental results showed that adding Cr could significantly improve the morphology of the primary phase in the Al-2.5Mn alloy. Without Cr, the primary phase in the alloy was thick, needle-like, and strip-like structure. After adding 0.2wt%-0.5wt% Cr, the primary phase in the upper part of the alloy was gradually fined and reached the best effect at 0.35wt% Cr. When the content of Cr was 0.5wt%, the microstructure of the primary phase in the upper part began to coarsen. The bottom of the alloy was a large bulk phase, but still much finer than that without adding Cr. XRD and SEM analysis showed that the precipitation phase at the bottom was mainly Al₈₅Mn₇Cr₈, while the fine microstructure at the top was Al₆Mn and Al₃Mn. The results of the cooling rate experiments showed that the primary phase of Al-2.5Mn-0.35Cr was further refined, and the eu-tectic microstructure was partly achieved, under air-cooling condition. And when the cooling method was iron die-cooling, the microstructure of the Al-2.5Mn-0.35Cr alloy was changed into a eutectic microstructure.

Keywords

Al-2.5Mn alloy / Cr content / primary phase / cooling rate

References

[1] Sun J, Xu SX, Tang J, Wang FF, Han ZQ. Development of squeeze casting technology for manufacturing aluminum alloy subframe for automobile. Foundry, 2015, 64, 17

[2] Park JH, Kim KJ, Lee JW, Yoon JK. Light-weight design of automotive suspension link based on design of experiment. Int. J. Automot. Technol., 2015, 16, 67.

[3] Ao XH, Xing SM, Yu BS, Han QY. Effect of Ce addition on microstructures and mechanical properties of A380 aluminum alloy prepared by squeeze-casting. Int. J. Miner. Metall. Mater., 2018, 25, 553.

[4] Farshidi MH, Rifai M, Miyamoto H. Microstructure evolution of a recycled Al-Fe-Si-Cu alloy processed by tube channel pressing. Int. J. Miner. Metall. Mater., 2018, 25, 1166.

[5] Pan FS, Zhang DF. Aluminum Alloy and Application, 2006 306

[6] Li XC. Microstructure and Metallographic Map of Aluminum Alloy Materials, 2010 1639

[7] Zhao Q, Wang SX. Selection and Design of Aluminum Alloys, 2017 20

[8] Wang XM. Engineering Materials Science, 2012 148

[9] Mraied H, Cai W. The effects of Mn concentration on the tribocorrosion resistance of Al-Mn alloys. Wear, 2017 191

[10] Chen XP, Li XG, Li S, Liu Q. aContinuous recrystal-lization of commercial Al-1.2wt%Mn alloy produced by thermomechanical processing. Mater. Lett., 2016, 180, 101.

[11] Li Z, Zhang Z, Chen XG. Effect of magnesium on dispersoid strengthening of Al-Mn-Mg-Si (3xxx) alloys. Trans. Nonferrous Met. Soc. China, 2016, 26, 2793.

[12] Sugamata M, Kaneko J, Kimura N. Structure and properties of rapidly solidified P/M samples of Al-Mn-Cr alloys. Mater. Sci. Forum, 2003 359

[13] Coury FG, Kiminami CS, Botta WJ, Bolfarini C, Kaufman M. Design and production of Al-Mn-Ce alloys with tailored properties. Mater. Des., 2016, 110, 436.

[14] Kula A, Blaz L, Lobry P. Structure and properties studies of rapidly solidified Al-Mn alloys. Key Eng. Mater., 2016, 682, 199.

[15] Luo DW, Guo J, Yan ZM, Li TJ. Effect of high magnetic fields on the solidification microstructure of an Al-Mn alloy. Rare Met., 2009, 28, 302.

[16] Dong YB, Liu Y, Lin H. Leaching behavior of V, Pb, Cd, Cr, and As from stone coal waste rock with different particle sizes. Int. J. Miner. Metall. Mater., 2018, 25, 861.

[17] Lin C, Wu SS, Lü SL, An P, Wu HB. Effects of high-pressure rheo-squeeze casting on the Fe-rich phases and mechanical properties of Al-17Si-(1,1.5)Fe alloys. Int. J. Miner. Metall. Mater., 2018, 25, 1018.

[18] Liu K, Chen XG. Evolution of microstructure and elevated-temperature properties with Mn addition in Al-Mn-Mg alloys. J. Mater. Res., 2017, 32, 1

[19] Zhen L, Zhan Z, Chen XG. Improvement in the mechanical properties and creep resistance of Al-Mn-Mg 3004 alloy with Sc and Zr addition. Mater. Sci. Eng. A, 2018, 729, 196.

[20] Coury FG, Pires EL, Wolf W, de Almeida FHP, e Silva ALC, Botta WJ, Kiminami CS, Kaufman MJ. Insight into the complex ternary phase behavior in Al-Mn-Ce alloys. J. Alloys Compd., 2017, 727, 460.

[21] Cui SL, Jung IH. Thermodynamic modeling of the Al-Cr-Mn ternary system. Metall. Mater. Trans. A, 2017, 48, 1383.

[22] Huang CQ, Liu JX, Jia XD. Effect of thermal deformation parameters on the microstructure, texture, and micro-hardness of 5754 aluminum alloy. Int. J. Miner. Metall. Mater., 2019, 26, 1140.

[23] Kang HJ, Li JL, Wang TM, Guo JJ. Growth behavior of primary intermetallic phases and mechanical properties for directionally solidified Al-Mn-Be alloy. Acta Metall. Sin., 2018, 54, 809

[24] Liu XC, Pan Y, Tang ZJ, He WQ, Lu T. Microstructure control and high temperature properties of Al-Mn-based alloys. Acta Metall. Sin., 2017, 53, 1487

[25] Raghavan V. Al-Mn-Ni-Ti (Aluminum-Manganese-Nickel-Titanium). J. Phase Equilib. Diffus., 2005, 26, 280.

[26] Ping L, Dunlop GL. Microstructural characterization of rapidly solidified Al-Mn-Cr alloys. Mater. Sci. Eng. A, 1991, 134, 1182.

[27] Razazi HA, Paidar M, Ojo OO. Effect of Mn and Cr on structure and mechanical properties of Al-10%Mg-0.1%Ti alloy. Vacuum, 2018, 155, 619.

[28] Hu GX, Cai X, Rong YH. Fundamentals of Materials Science, 2010 231

[29] He YD, Zhang XM. Refinement mechanism of trace Cr, Mn, Ti and Zr as cast 7A55 alloys. Chin. J. Nonferrous Met., 2005, 15, 1594

[30] Birol Y. Effect of Cr and Zr on the grain structure of extruded EN AW 6082 alloy. Met. Mater. Int., 2014, 20, 727.

[31] Hu HQ. Principle of Metal Solidification, 2017 173

[32] Zhang Y, Du WB, Li SB, Liu K, Wang CH, Zheng XB. Effect of cooling rate on solidification structure of Mg-8Gd-1Er alloy. Rare Met. Mater. Eng., 2018, 47, 3120