Strengthening mechanisms in cryomilled ultrafine-grained aluminum alloy at quasi-static and dynamic rates of loading

Cao, Benyi; Joshi, Shailendra P.; Ramesh, K.T.

doi:10.1016/j.scriptamat.2008.12.026

Cited by 64 publications

(28 citation statements)

References 25 publications

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“…This is an increase in strength of approximately 400 MPa as compared with commercially available CG Al-5083 H131 also tested at dynamic strain rates [31] and is a result of the reduced grain size through the Hall-Petch effect and nanoprecipitates produced during cryomilling [1]. The room temperature results also show a very weak strain hardening behavior, in contrast to the strain hardening observed for commercially available CG Al-5083 H131(This is demonstrated in [31]).…”

Section: Resultsmentioning

confidence: 81%

“…A similar pattern is observed at QS rates. The flow stress of the QS tests is lower than that of dynamic tests (~100 MPa) due to positive rate sensitivity of this material at dynamic strain rates [1]. The QS results show a maximum flow stress at low strains followed by nearly perfectly plastic behavior, and perhaps even weak strain softening.…”

Section: Resultsmentioning

confidence: 83%

“…The room temperature results also show a very weak strain hardening behavior, in contrast to the strain hardening observed for commercially available CG Al-5083 H131(This is demonstrated in [31]). This phenomenon is commonly observed with cryomilled UFG materials [1,32]. For UFG materials, the reduced size of the grain interior limits the amount of dislocation accumulation as mobile dislocations will often reach a grain boundary and annihilate before interacting with another dislocation.…”

Section: Resultsmentioning

confidence: 90%

“…One material system that shows promise is the aluminum alloy system, since these alloys have a relatively low density and can be significantly strengthened through grain size refinement [1][2][3] and particle-reinforcement [4,5]. The observed flow stresses of these aluminum-based materials depend on the microstructure of the material and also the strain rate and temperature associated with the loading.…”

Section: Introductionmentioning

confidence: 99%

“…We note that the microstructural variables S may evolve as a result of plastic deformation, and consequentially many constitutive descriptions use the plastic strain as a surrogate for S. For many materials the mechanical properties of greatest interest are those related to derivatives of the flow stress. From equation (1), the strain rate sensitivity may be defined as either d ln s d ln Á ( T ;( or d ln s d ln Á ( T;S ; both of these are used within the literature, but we use the former within this paper. The change in flow stress due to a change in microstructure is defined as ds dS T; Á we define the thermal softening as ds dT Á ( ;( .…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Temperature-Dependent Mechanical Response of an UFG Aluminum Alloy at High Rates

Huskins

Cao

et al. 2011

Exp Mech

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High temperature (298 K-573 K) and high strain rate (4000 s −1 ) compression experiments were performed on a cryomilled ultra-fine grained (UFG) Al-5083 using a modified Kolsky bar with a heating system designed to reduce "cold contact" time. The resulting stress strain curves show a reduction in strength of approximately 300 MPa at the highest temperature tested. This softening has been related to a thermally activated deformation mechanism. In addition, an experimental procedure was developed to investigate the microstructure evolution during the preheating, prior to mechanical loading, so as to identify the intrinsic mechanical response of the material at high temperatures. The results of this procedure are in good agreement with a TEM study on material that has been heated but not loaded.

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Section: Resultsmentioning

confidence: 81%

Section: Resultsmentioning

confidence: 83%

Section: Resultsmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Temperature-Dependent Mechanical Response of an UFG Aluminum Alloy at High Rates

Huskins

Cao

et al. 2011

Exp Mech

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On the Estimation of True Hall–Petch Constants and Their Role on the Superposition Law Exponent in Al Alloys

et al. 2012

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Hall–Petch (HP) relation and the superposition of different strengthening mechanisms in different aluminum alloys with grain sizes in the range of 50 nm–70 µm were analyzed. HP parameters as high as σ0 ≈ 200 MPa and kHP ≈ 0.14 MPa m1/2 were observed when the HP relation was fitted directly using the experimentally measured yield strength values. In contrast, considering only the grain size strengthening (by subtracting other strengthening contributions), HP constants of σ0 ≈ 10 MPa and kHP ≈ 0.06 MPa m1/2 were obtained over wide range of grain sizes for the case of a linear superposition of the various strengthening mechanisms present. This is in excellent accord with the values obtained for pure Al justifying the chosen superposition exponent of n equal unity for the different alloys investigated.

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Development of High Performance of Al Alloys via Cryo‐Forming: A Review

Xiong

Su²,

Kong

et al. 2021

Adv Eng Mater

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Weight reduction is a major trend in the development of automotive, marine, and aerospace industry. Al alloys are the ideal choice for the lightweight design because of their superior mechanical properties and small mass density. In recent years, research results have demonstrated that plastic processing at cryogenic temperature can improve the mechanical properties of Al alloys. Herein, the mechanical properties of Al alloys at cryogenic environment as well as at room temperature are compared, and then the main progress is introduced in the development of fabrication of high‐performance Al alloys using cryo‐forming methods, such as cryorolling, asymmetric cryorolling, cryo‐extrusion, and cryo‐forging, with subsequent heat treatment. The grain refinement mechanism and the strengthening mechanism of Al alloys during various cryo‐forming processes are discussed. Finally, the potential development prospects of future researches in this field are proposed.

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Strengthening mechanisms in cryomilled ultrafine-grained aluminum alloy at quasi-static and dynamic rates of loading

Cited by 64 publications

References 25 publications

Temperature-Dependent Mechanical Response of an UFG Aluminum Alloy at High Rates

Temperature-Dependent Mechanical Response of an UFG Aluminum Alloy at High Rates

On the Estimation of True Hall–Petch Constants and Their Role on the Superposition Law Exponent in Al Alloys

Development of High Performance of Al Alloys via Cryo‐Forming: A Review

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