Enhancement of Hardness Related Properties of Grey Cast Iron Powder Reinforced AA7075 Metal Matrix Composites through T6 and T8 Heat Treatments
In present global scenario, aluminum alloys are
coining the attention of many innovators as competing structural
materials for automotive and space applications. Comparing to other
challenging alloys, especially, 7xxx series aluminum alloys have
been studied seriously because of benefits such as moderate strength;
better deforming characteristics and affordable cost. It is expected
that substitution of aluminum alloys for steels will result in great
improvements in energy economy, durability and recyclability.
However, it is necessary to improve the strength and the formability
levels at low temperatures in aluminum alloys for still better
applications. Aluminum–Zinc–Magnesium with or without other
wetting agent denoted as 7XXX series alloys are medium strength
heat treatable alloys. In addition to Zn, Mg as major alloying
additions, Cu, Mn and Si are the other solute elements which
contribute for the improvement in mechanical properties by suitable
heat treatment process. Subjecting to suitable treatments like age
hardening or cold deformation assisted heat treatments; known as low
temperature thermomechanical treatments (LTMT) the challenging
properties might be incorporated. T6 is the age hardening or
precipitation hardening process with artificial aging cycle whereas T8
comprises of LTMT treatment aged artificially with X% cold
deformation. When the cold deformation is provided after solution
treatment, there is increase in hardness related properties such as
wear resistance, yield and ultimate strength, toughness with the
expense of ductility. During precipitation hardening both hardness
and strength of the samples are increasing. The hardness value may
further improve when room temperature deformation is positively
supported with age hardening known as thermomechanical treatment.
It is intended to perform heat treatment and evaluate hardness, tensile
strength, wear resistance and distribution pattern of reinforcement in
the matrix. 2 to 2.5 and 3 to 3.5 times increase in hardness is reported
in age hardening and LTMT treatments respectively as compared to
as-cast composite. There was better distribution of reinforcements in
the matrix, nearly two fold increase in strength levels and up to 5
times increase in wear resistance are also observed in the present
study.
[1] Berg L. K, Gjonnes J, Hansen V, Li X. Z, Knutson-wedel, & M,
Waterloo G “GP-zones in Al–Zn–Mg alloys and their role in artificial
aging” Acta Mater 2001;49:3443–3465.
[2] Song R. G & Zhang Q. Z, “Heat treatment optimization for
7175aluminum alloy by genetic algorithm.” Material Science
Engineering, C 2001; 17:133–137.
[3] Tangen Stian, Sjolstad Knut, Nes Erik, Furu Trond & Marthinsen Knut,
“The effect of precipitation on the recrystallization behavior of a
supersaturated, cold rolled AA3103 aluminium alloy”, Material Science
Forum 2002; 469:396–402.
[4] Lee S. H, Saito Y, Sakai T & Utsunomiya H, “Microstructures and
mechanical properties of 6061 aluminum alloy processed by
accumulative roll-bonding”, Material Science Engineering A,
2002;325:228–235.
[5] Robson J. D, “Optimizing the homogenization of zirconium containing
commercial aluminium alloys using a novel process model”, Material
Science Engineering A 2002; 338:219–229.
[6] Chen S. P, Kuijpers NCW & Van der Zwaag S, “Effect of
microsegregation and dislocations on the nucleation kinetics of
precipitation in aluminium alloy AA3003”, Material Science
Engineering A, 2003;341:296.
[7] Starink M. J & Wang S. C, “A model for the yield strength of overaged
Al–Zn–Mg–Cu alloys”, Acta Mater, 2003; 51:5131–5150.
[8] Chen K. H, Liu H. W, Zhang Z, Li S & Todd R. I, “The improvement of
constituent dissolution and mechanical properties of 7055 aluminum
alloy by stepped heat treatments”, Journal of Material Process
Technology, 2003; 142:190–196.
[9] Dumont D, Deschamps A & Brechet Y, “On the relationship between
microstructure, strength and toughness in AA7050aluminum alloy”,
Material Science Engineering A 2003; 356: 326–326.
[10] Wang D, Nia D. R & Ma Z. Y, “Effect of pre-strain and two-stepaging
on microstructure and stress corrosion cracking of 7050alloy”, Material
Science Engineering A, 2008 ; 218-226.[11] E. Sjolender & S. Seifeddine, “Optimization of solution treatment of cast
Al-Si-Cu alloys”, Materials and Design, 2010; 31; 544-549.
[12] Norbert Ponweiser & Klauss W. Richter, “New investigation of phase
equilibria in the system Al -Cu-Si”, Alloys and Compounds, 2012; 512;
252-253.
[13] V. C. Yuvaraja & N. Natarajan,”Comparison on Al6061 and Al7075
Alloy with Sic and B4c reinforcement Hybrid Metal Matrix
Composites”, Int. Journal of Advanced Research in Tech., 2, , 2012,1-
12.
[14] G. B. Veeresh Kumar, C. S. P. Rao, N. Selvaraj, & M. S. Bhagyashekar
,”Studies on Al6061-SiC and Al7075-Al2O3 Metal Matrix Composites”,
Journal of Minerals & Materials Characterization & Engineering, 9,
2010 ;43-55.
[15] Wang H.Q, Sun W.L & Xing Y.Q,” Microstructure Analysis on 6061
Aluminum Alloy after Casting and Diffuses Annealing Process”,
Physics Procedia-Elsevier, 2013, 1, 68 – 75.
[1] Berg L. K, Gjonnes J, Hansen V, Li X. Z, Knutson-wedel, & M,
Waterloo G “GP-zones in Al–Zn–Mg alloys and their role in artificial
aging” Acta Mater 2001;49:3443–3465.
[2] Song R. G & Zhang Q. Z, “Heat treatment optimization for
7175aluminum alloy by genetic algorithm.” Material Science
Engineering, C 2001; 17:133–137.
[3] Tangen Stian, Sjolstad Knut, Nes Erik, Furu Trond & Marthinsen Knut,
“The effect of precipitation on the recrystallization behavior of a
supersaturated, cold rolled AA3103 aluminium alloy”, Material Science
Forum 2002; 469:396–402.
[4] Lee S. H, Saito Y, Sakai T & Utsunomiya H, “Microstructures and
mechanical properties of 6061 aluminum alloy processed by
accumulative roll-bonding”, Material Science Engineering A,
2002;325:228–235.
[5] Robson J. D, “Optimizing the homogenization of zirconium containing
commercial aluminium alloys using a novel process model”, Material
Science Engineering A 2002; 338:219–229.
[6] Chen S. P, Kuijpers NCW & Van der Zwaag S, “Effect of
microsegregation and dislocations on the nucleation kinetics of
precipitation in aluminium alloy AA3003”, Material Science
Engineering A, 2003;341:296.
[7] Starink M. J & Wang S. C, “A model for the yield strength of overaged
Al–Zn–Mg–Cu alloys”, Acta Mater, 2003; 51:5131–5150.
[8] Chen K. H, Liu H. W, Zhang Z, Li S & Todd R. I, “The improvement of
constituent dissolution and mechanical properties of 7055 aluminum
alloy by stepped heat treatments”, Journal of Material Process
Technology, 2003; 142:190–196.
[9] Dumont D, Deschamps A & Brechet Y, “On the relationship between
microstructure, strength and toughness in AA7050aluminum alloy”,
Material Science Engineering A 2003; 356: 326–326.
[10] Wang D, Nia D. R & Ma Z. Y, “Effect of pre-strain and two-stepaging
on microstructure and stress corrosion cracking of 7050alloy”, Material
Science Engineering A, 2008 ; 218-226.[11] E. Sjolender & S. Seifeddine, “Optimization of solution treatment of cast
Al-Si-Cu alloys”, Materials and Design, 2010; 31; 544-549.
[12] Norbert Ponweiser & Klauss W. Richter, “New investigation of phase
equilibria in the system Al -Cu-Si”, Alloys and Compounds, 2012; 512;
252-253.
[13] V. C. Yuvaraja & N. Natarajan,”Comparison on Al6061 and Al7075
Alloy with Sic and B4c reinforcement Hybrid Metal Matrix
Composites”, Int. Journal of Advanced Research in Tech., 2, , 2012,1-
12.
[14] G. B. Veeresh Kumar, C. S. P. Rao, N. Selvaraj, & M. S. Bhagyashekar
,”Studies on Al6061-SiC and Al7075-Al2O3 Metal Matrix Composites”,
Journal of Minerals & Materials Characterization & Engineering, 9,
2010 ;43-55.
[15] Wang H.Q, Sun W.L & Xing Y.Q,” Microstructure Analysis on 6061
Aluminum Alloy after Casting and Diffuses Annealing Process”,
Physics Procedia-Elsevier, 2013, 1, 68 – 75.
@article{"International Journal of Chemical, Materials and Biomolecular Sciences:70517", author = "S. S. Sharma and P. R. Prabhu and K. Jagannath and Achutha Kini U. and Gowri Shankar M. C.", title = "Enhancement of Hardness Related Properties of Grey Cast Iron Powder Reinforced AA7075 Metal Matrix Composites through T6 and T8 Heat Treatments", abstract = "In present global scenario, aluminum alloys are
coining the attention of many innovators as competing structural
materials for automotive and space applications. Comparing to other
challenging alloys, especially, 7xxx series aluminum alloys have
been studied seriously because of benefits such as moderate strength;
better deforming characteristics and affordable cost. It is expected
that substitution of aluminum alloys for steels will result in great
improvements in energy economy, durability and recyclability.
However, it is necessary to improve the strength and the formability
levels at low temperatures in aluminum alloys for still better
applications. Aluminum–Zinc–Magnesium with or without other
wetting agent denoted as 7XXX series alloys are medium strength
heat treatable alloys. In addition to Zn, Mg as major alloying
additions, Cu, Mn and Si are the other solute elements which
contribute for the improvement in mechanical properties by suitable
heat treatment process. Subjecting to suitable treatments like age
hardening or cold deformation assisted heat treatments; known as low
temperature thermomechanical treatments (LTMT) the challenging
properties might be incorporated. T6 is the age hardening or
precipitation hardening process with artificial aging cycle whereas T8
comprises of LTMT treatment aged artificially with X% cold
deformation. When the cold deformation is provided after solution
treatment, there is increase in hardness related properties such as
wear resistance, yield and ultimate strength, toughness with the
expense of ductility. During precipitation hardening both hardness
and strength of the samples are increasing. The hardness value may
further improve when room temperature deformation is positively
supported with age hardening known as thermomechanical treatment.
It is intended to perform heat treatment and evaluate hardness, tensile
strength, wear resistance and distribution pattern of reinforcement in
the matrix. 2 to 2.5 and 3 to 3.5 times increase in hardness is reported
in age hardening and LTMT treatments respectively as compared to
as-cast composite. There was better distribution of reinforcements in
the matrix, nearly two fold increase in strength levels and up to 5
times increase in wear resistance are also observed in the present
study.", keywords = "Reinforcement, precipitation, thermomechanical,
dislocation, strain hardening.", volume = "9", number = "6", pages = "725-7", }