Combined Effects of Pre-deformation and Pre-aging on the Mechanical Properties of Al-Cu-Mg Alloy with Sc and Zr Addition

Abstract

The combined effects of pre-deformation and pre-aging on the mechanical properties of Al-Cu-Mg alloy with Sc and Zr addition were investigated. It is revealed that the introduction of pre-deformation can enhance the peak-aging strength, as well as tensile and yield strength, effectively due to the formation of finer and more dispersive precipitation. Pre-aging process before pre-deformation can increase the elongation while maintaining higher strength with a discontinuous distribution of precipitates at grain boundary. The precipitates of bean-like Al₃(Sc, Zr) particles further strengthen the alloy via pinning the dislocations which are formed during pre-deformation process and hindering the dislocation motion. Furthermore, pre-deformation and pre-aging accelerate the kinetics of precipitation due to preferential sites provided by the dislocation and the increase of GPB zones’ size and distribution. The synergism of pre-deformation and pre-aging achieves a combination of better mechanical properties and shorter peak-aging time.

Keywords

pre-deformation / pre-aging / mechanical properties / Al-Cu-Mg-Sc-Zr alloy

References

[1] Wang S C, Starink M J, Gao N. Precipitation Hardening in Al-Cu-Mg Alloys Revisited[J]. Scripta Mater., 2006, 54: 287-291.

[2] Ringer S P, Quan G C, Sakurai T. Solute Clustering, Segregation and Microstructure in High Strength Low Alloy Al-Cu-Mg Alloys[J]. Mater. Sci. Eng. A, 1998, 250: 120-126.

[3] Yang S, Yi D Q, Zhang H, et al. Flow Stress Behavior and Processing Map of Al-Cu-Mg-Ag Alloy during Hot Compression[J]. J. Wuhan. Univ. Tech.-Mat. Sci. Edi., 2008, 23(5): 694-698.

[4] Chen X, Liu Z Y, Bai S, et al. Alloying Behavior of Erbium in an Al-Cu-Mg Alloy[J]. J. Alloy. Compd., 2010, 505: 201-205.

[5] Liu L, Chen J H, Wang S B, et al. The Effect of Si on Precipitation in Al–Cu–Mg Alloy with a High Cu/Mg Ratio[J]. Mater. Sci. Eng. A, 2014, 606: 187-195.

[6] Banerjee S, Robi P S, Srinivasan A, et al. Effect of Trace Additions of Sn on Microstructure and Mechanical Properties of Al-Cu-Mg Alloys[J]. Mater. Des., 2010, 31: 4007-4015.

[7] Gazizov M, Teleshov V, Zakharov V, et al. Solidification Behaviour and the Effects of Homogenisation on the Structure of an Al-Cu-Mg-Ag-Sc Alloy[J]. J. Alloy. Compd., 2011, 509: 9497-9507.

[8] Hutchinson C R, Fan X, Pennycook S J. On the Origin of the High Coarsening Resistance of O Plates in Al–Cu–Mg–Ag Alloys[J]. Acta Mater., 2001, 49: 2827-2841.

[9] Jiang F, Wen K, Jian H G, et al. Existing Form and Action Mechanism of Minor Scandium and Zirconium in Al-Cu-Mg Alloy[J]. Cent. South Univ. T., 2010, 17: 19-23.

[10] Esmaeili S, Lloyd D J, Jin H. A Thermomechanical Process for Grain Refinement in Precipitation Hardening AA6xxx Aluminum Alloys[J]. Mater. Lett., 2011, 65: 1028-1030.

[11] Wang Z X, Li H, Miao F F, et al. Improving the Strength and Ductility of Al-Mg-Si-Cu Alloys by a Novel Thermo-mechanical Treatment[J]. Mater. Sci. Eng. A, 2014, 607: 313-317.

[12] Mansourinejad M, Mirzakhani B. Influence of Sequence of Cold Working and Aging Treatment on Mechanical Behaviour of 6061 Aluminum Alloy[J]. Trans. Nonferrous Met. Soc. China, 2012, 22: 2072-2079.

[13] Kolar M, Pederson K O, Dahl S G, et al. Combined Effect of Deformation and Artificial Aging on Mechanical Properties of Al-Mg-Si Alloy[J]. Trans. Nonferrous Met. Soc. China, 2012, 22: 1824-1830.

[14] Emani S V, Benedyk J, Nash P, et al. Double Aging and Thermomechanical Heat Treatment of AA7075 Aluminum Alloy Extrusions[J]. J. Mater. Sci., 2009, 44: 6384-6391.

[15] Kovarika L, Court S A, Fraser H L, et al. GPB Zones and Composite GPB/GPBII Zones in Al-Cu-Mg Alloys[J]. Acta Mater., 2008, 56: 4804-4815.

[16] Parel T S, Wang S C, Starink M J. Hardening of an Al-Cu-Mg Alloy Containing Types I and II S Phase Precipitates[J]. Mater. Des., 2010, 31: S2-S5.

[17] Wang S C, Starink M J. Two Types of S Phase Precipitates in Al-Cu-Mg Alloys[J]. Acta Mater., 2007, 55: 933-941.

[18] Ringer S P, Hono K, Sakurai T. Cluster Hardening in an Aged Al-Cu-Mg Alloy[J]. Scripta Mater., 1997, 36: 517-521.

[19] Kovarik L, Gouma P I, Kisielowski C. A HRTEM Study of Metastable Phase Formation in Al-Mg-Cu Alloys during Artificial Aging[J]. Acta Mater., 2004, 52: 2509-2520.

[20] Forbord B, Lefebvre W, Danoix F, et al. Three Dimensional Atom Probe Investigation on the Formation of Al3(Sc,Zr)-dispersoids in Aluminium Alloys[J]. Scripta Mater., 2004, 51: 333-337.

[21] Lefebvre W, Danoix F, Hallem H, et al. Precipitation Kinetic of Al3(Sc,Zr) Dispersoids in Aluminium[J]. J. Alloy. Compd., 2009, 470: 107-110.

[22] Seidman D N, Marquis E A, Dunand D C. Precipitation Strengthening at Ambient and Elevated Temperatures of Heat-treatable Al(Sc) Alloys[J]. Acta Mater., 2002, 50: 4021-4035.

[23] Jiang L, Li J K, Liu G. Length-Scale Dependent Microalloying Effects on Precipitation Behaviors and Mechanical Properties of Al-Cu Alloys with Minor Sc Addition[J]. Mater. Sci. Eng. A, 2015, 637: 139-154.