In the present paper, the microstructure and mechanical properties of a precipitation hardening Al-Cu (2219) alloy subjected to cryorolling, low temperature annealing and ageing treatments are reported. Under optimal processing conditions, ultrafine grained microstructure with improved tensile strength (540 MPa) and good ductility (11% tensile elongation) was obtained. © 2006 Acta Materialia Inc.

Budaraju Srinivasa Murty

Department of Metallurgical and Materials Engineering

V. Subramanya Sarma

Aging of materials

Annealing

Ductility

Grain growth

Hot rolling

microstructure

Tensile strength

AL-CU ALLOY

CRYOROLLING

Precipitation

ULTRAFINE GRAINED MICROSTRUCTURE

Aluminum Copper Alloys

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Scripta Materialia

In the present work, cryorolling (CR) (rolling temperature is − 196 °C) followed by annealing (AN) (100–400 °C for 1 h) of 6082 Al alloy has been performed. The main objective of this study was to investigate the thermal stability of the ultrafine-grained 6082 Al alloy, for higher temperature applications. The mechanical properties of the CR and the CR + AN 6082 Al alloy were investigated and correlated with the microstructure with the help of a transmission electron microscope (TEM). The hardness and the tensile strength of the CR + AN (150 °C) 6082 Al alloy were significantly improved up to 95% and 40%, respectively, when compared to the solution-treated (ST) 6082 Al alloy. The main reason behind the mechanical strength improvement was dislocation strengthening and precipitation strengthening. Thermal stability of the CR 6082 Al alloy was found up to a high annealing temperature of 300 °C due to the pinning of grain boundaries by precipitates evaluation during annealing by Zener drag effect. The formation of β″-phase, β′-phase and stable β-phase occurred at the annealing temperatures of 175 °C for 1 h, 200 °C for 1 h and 250 °C for 1 h, respectively. © 2019, The Indian Institute of Metals - IIM.

Transactions of the Indian Institute of Metals

Effect of Annealing on Mechanical Properties and Metallurgical Factors of Ultrafine-Grained 6082 Al Alloy

High crushing force and good energy absorption are the essential requirements for structural materials subjected to dynamic loading. In the present work, commercial A356 material is subjected to cryorolling and post-cryoroll annealing to produce sheets of different grain sizes and the influence of microstructural change on dynamic behavior of the material is studied. Dynamic tests are done in a crossbow test equipment at an average strain rate of 250 s−1. Quasi-static tests are done at an initial strain rate of 0.005 s−1 to compare the dynamic performance of the material with its static/quasi-static behavior. It is found that strength and ductility of cryorolled material at dynamic loading condition is lesser than that in quasi-static loading. Upon annealing, the material performance of the material is found to be better at high strain-rate deformation than that at quasi-static condition. A detailed analysis on the deformation behavior and fracture mechanism of the material at high strain-rate is carried out. Further, the existence of Hall-Petch relationship at high strain-rate deformation is evaluated. The material's strengthening factor is found to hold good agreement to the Hall-Petch relationship with a grain boundary strengthening coefficient of 112 MPa at dynamic loading. © 2017 Elsevier B.V.

Materials Science and Engineering A

Investigation on crashworthiness of ultrafine grained A356 sheets and validation of Hall-Petch relationship at high strain-rate deformation

Ultrafine grained AA7075 aluminum alloy (Al–6Zn–2Mg–1Cu), was produced by cryorolling the solutionized samples followed by annealing and peak aging treatments. In the cryorolled and peak aged (CRPA) alloy, the presence of large amount of dislocations acted as nucleation sites for precipitation, resulting in finer and densely distributed precipitates, when compared to its coarse grain peak aged (CGPA) alloy. Potentiodynamic polarization studies revealed increased Epit by about 300&nbsp;mV for CRPA alloy compared to CGPA alloy, indicating improved corrosion resistance to pitting. Intergranular corrosion tests were performed according to ASTM G-110 and the results revealed no grain boundary attack and improved resistance of CRPA when compared to severe grain boundary attack in CGPA alloy. The improved corrosion resistance in CRPA was mainly attributed to the reduced galvanic couples formation within the alloy due to absence of anodic coarse precipitates along the grain boundaries and the associated precipitate free zones. © 2017, The Indian Institute of Metals - IIM.

Studies on Aging and Corrosion Properties of Cryorolled Al–Zn–Mg–Cu (AA7075) Alloy

A combination of high strength and good ductility was achieved in a precipitation hardenable Cu-3Ag-0.5Zr alloy through cryo-rolling (80% reduction in thickness) and aging in the temperature range (200-500 °C). The high-strength sheets produced by cryo-rolling showed a threefold increase in yield strength compared to that of the solution-treated and aged (220 MPa) sample, while retaining good ductility. An optimum combination of high strength (614 MPa) and ductility (8%) was achieved by 80% cryo-rolling and aging at 320 °C for 1 h. The high strength and good ductility obtained was attributed to various microstructural factors such as deformation twins, ultra-fine grains, high dislocation density and fine nano-sized silver precipitates. © 2016, ASM International.

Journal of Materials Engineering and Performance

High Strength and Good Ductility in Cu-3Ag-0.5Zr Alloy by Cryo-Rolling and Aging

The tensile and fracture behavior of ultrafine-grained Al 6061 alloy has been studied by experimental testing and extended finite element method simulation. The ultrafine-grained alloy processed by cryorolling has been produced from its bulk alloy with different thickness reductions. Microstructural features have been evaluated by electron backscattered diffraction. The EBSD results show the formation of subgrains and large number of high-angle grain boundaries in the rolled Al alloy. Mechanical behavior has been investigated using microhardness, tensile test, fracture toughness, and fractography of all samples. The extended finite element method has been used to investigate elastic–plastic deformation behavior of ultrafine-grained Al 6061 alloy. The extended finite element method has been used to simulate tensile and fracture behavior of ultrafine-grained alloy with material constants evaluated from experimentally measured tensile properties. Simulated tensile and fracture properties are in tandem with the experimental results. Ultrafine-grained Al 6061 alloy has shown better tensile strength and fracture toughness as evident from experimental and simulation results. © 2017, Springer Science+Business Media New York and ASM International.

Metallography, Microstructure, and Analysis

Experimental and XFEM Simulation of Tensile and Fracture Behavior of Al 6061 Alloy Processed by Severe Plastic Deformation

Influence of cryo-rolling reduction and annealing of commercially pure (CP) Al is evaluated in four aspects: microstructure, mechanical properties, electrical conductivity and general corrosion. It is shown that by selecting optimal cryo-rolling reduction and subsequent annealing condition result in ultrafine grains in CP Al with good combination of high strength and ductility. Electrical conductivity of the cryo-rolled samples decreased due to increased number of the electron scattering centers (lattice defects and grain boundary area). However, optimization of cryo-rolling and annealing treatment could restore the conductivity coupled with high strength in CP Al. Corrosion behaviour of cryo-rolled CP Al improved after annealing treatment. High dissolution rate and low thermal stability of the ultrafine grain structure could override the anticipated advantage of uniform corrosion in ultrafine grain CP Al. © 2005 Elsevier B.V. All rights reserved.

Effect of cryo-rolling and annealing on microstructure and properties of commercially pure aluminium

Materials Science and Engineering: A

The tensile behavior and deformation microstructure of cryo-rolled and annealed pure nickel

Large enhancement in mechanical properties of the 6061 Al alloys after a single pressing by ECAP

Advanced Materials

Achieving High Strength and High Ductility in Precipitation-Hardened Alloys

Tensile strength and ductility of ultra-fine-grained nickel processed by severe plastic deformation

Development of ultrafine grained high strength Al-Cu alloy by cryorolling

Journal	Scripta Materialia
ISSN	13596462
Open Access	No