Effect of melt conditioning on heat treatment and mechanical properties of AZ31 alloy strips produced by twin roll casting

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:620

Article

Das, Sanjeev¹  Barekar, N. S.¹  El Fakir, Omer²  Wang, Liliang²  Rao, A. K. Prasada¹  Patel, J. B.¹  Kotadia, H. R.¹  Bhagurkar, A.¹  Dear, John P.²  Fan, Z.¹ 

[1] Brunel Univ, BCAST, LiME, EPSRC Ctr, Uxbridge UB8 3PH, Middx, England

[2] Univ London Imperial Coll Sci Technol & Med, Dept Mech Engn, London SW7 2AZ, England

关键词: Twin roll casting;    Solidification;    Tensile test;    Fracture analysis;    Optical and scanning electron microscopy;   

DOI  :  10.1016/j.msea.2014.10.019

来源: Elsevier

【 摘 要 】

In the present investigation, magnesium strips were produced by twin roll casting (TRC) and melt conditioned twin roll casting (MC-TRC) processes. Detailed optical microscopy studies were carried out on as-cast and homogenized TRC and MC-TRC strips. The results showed uniform, fine and equiaxed grain structure was observed for MC-TRC samples in as-cast condition. Whereas, coarse columnar grains with centreline segregation were observed in the case of as-cast TRC samples. The solidification mechanisms for TRC and MC-TRC have been found completely divergent. The homogenized TRC and MC-TRC samples were subjected to tensile test at elevated temperature (250-400 degrees C). At 250 degrees C, MC-TRC sample showed significant improvement in strength and ductility. However, at higher temperatures the tensile properties were almost comparable, despite of TRC samples having larger grains compared to MC-TRC samples. The mechanism of deformation has been explained by detailed fractures surface and sub-surface analysis carried out by scanning electron and optical microscopy. Homogenized MC-TRC samples were formed (hot stamping) into engineering component without any trace of crack on its surface. Whereas, TRC samples cracked in several places during hot stamping process. (C) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

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