Mechanical Behavior and Deformation Kinetics of Aluminum Alloys Processed through Cryorolling and Subsequent Annealing

Changela, Kandarp; Hariharan, K.; Digavalli, Ravi Kumar

doi:10.1007/s11661-019-05532-2

Cited by 18 publications

(9 citation statements)

References 61 publications

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“…In contrast, the k 2 values in ECAPed specimens are higher than for the as‐received specimen, which indicates the most active dynamic annihilation and recovery mechanisms operating during deformation in the ECAed specimens. According to Changela et al, [ 58 ] in an arbitrary dislocation structure, dislocations are much more easily eliminated when dislocations are not well‐organized forming stable cell arrangements. Table 3 allows observing that k 2 increases until the fifth pass and then decreases to reach stabilization at strains higher than six ECAP passes.…”

Section: Resultsmentioning

confidence: 99%

Strain‐Hardening Behavior in an AA6060‐T6 Alloy Processed by Equal Channel Angular Pressing

Khelfa

Muñoz-Bolaños

et al. 2020

Adv Eng Mater

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Strain hardening is a useful mechanism for improving mechanical properties in materials. This study investigates the strain‐hardening behavior of an AA6060 alloy processed by equal channel angular pressing (ECAP) up to 12 passes. Analysis by electron backscattered diffraction (EBSD) shows that the average geometrically necessary dislocations (GNDs) density increases continually up to the fourth pass and then saturates at a value of ≈1.85 × 1014 m−2. Hollomon and Kocks–Mecking–Estrin (KME) analysis are used to investigate the strain‐hardening behavior of the resulting ultrafine‐grained alloy. Results indicate that the strain‐hardening capacity (HC) and the strain‐hardening exponent (n) of all deformed specimens are lower in comparison with the as‐received condition. Moreover, the strain‐hardening rate fluctuates with the ECAP passes. First, it increases from the first ECAP pass up to the fourth pass, then diminishes up to the fifth pass, and finally, it increases again with further deformation. The difference in the strain‐hardening behavior of the ECAPed AA6060 is examined in terms of the grain size effect. It is shown that the strain‐hardening curves change notably with diminishing the grain size. In addition, the KME model is used to depict the storage and annihilation of dislocations in the ECAPed specimens.

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Section: Resultsmentioning

confidence: 99%

Strain‐Hardening Behavior in an AA6060‐T6 Alloy Processed by Equal Channel Angular Pressing

Khelfa

Muñoz-Bolaños

et al. 2020

Adv Eng Mater

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“…After combining equation ( 5) and the elementary integration of equation ( 9), the flow stress becomes the function of strain as given in equation (10). It is important to consider a factor (σ 0 ) in equation ( 10) which accounts for the interaction of dislocations-grain boundaries, dislocationssolute atoms, and mutual dislocations during plastic deformation.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…, are achieved. The values of K 1 and K 2 can be identified by simply fitting equation (10) with a uniaxial tensile curve. Further, the total dislocation density is evaluated using the parameters of dislocations storage (K 1 ) and dislocations recovery (K 2 ) which contributes to strain hardening during SPD or uniaxial tensile loading.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…Further, the total dislocation density is evaluated using the parameters of dislocations storage (K 1 ) and dislocations recovery (K 2 ) which contributes to strain hardening during SPD or uniaxial tensile loading. From equation (10), the evolution of total dislocation density with the function of strain is expressed in equation ( 11)…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…5,8 Apart from CGP, inhomogeneous grain refinement is always present in all the SPD processes though it is lower in the last passes. 9 Sometimes highly distorted microstructure, which is difficult to analyze optically, 10 is observed due to a large strain imposed during the process. Hence, transient tests such as stress relaxation test, strain rate jump test, and creep test are advantageous over the optical microstructure analysis as the former gives the median quantity of metallurgical parameters such as an average activation volume and dominant deformation mechanism.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Re-examination and comparison of activation volume, strain rate sensitivity, and dislocation density for coarse grain and CGP-processed UFG materials

Kumar

2023

Proceedings of the Institution of Mechanical Engineers, Part L:

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The frequently used metallurgical parameters such as activation volume, internal stress, strain rate sensitivity, and dislocation density are identified in ultrafine-grained (UFG) materials through erudite analytical relations. It is difficult to analyze such parameters optically since the material consists of highly distorted and inhomogeneous microstructure due to the large strain imposed during the constrained groove pressing (CGP) process. Hence, transient tests like stress relaxation tests are advantageous over the optical to use. Apart from the identification of parameters in low-carbon steel materials using uniaxial loading and stress relaxation tests, the relationship between the parameters is nobly investigated in as-received and UFG structure samples produced through the CGP process. In the relationship, the exponential-power law constitutive to describe the accurate stress–strain curves, identification of mobile and forest dislocation density during strain hardening, and exponential variation between grain size and activation volume are proposed. The replenishment or exhaustion of mobile and forest dislocation density significantly affects the metallurgical parameters during uniaxial tensile loading followed by stress relaxation testing. In this experimental and analytical work, the CGP process produces a UFG material that has lower activation volume and higher stress drop, mobile dislocation density, forest dislocations density, strain rate sensitivity, and internal stress.

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Stress Relaxation Study of Ultrafine-Grained AA 6061 Alloy Processed Through Combined Constrained Groove Pressing and Cold Rolling

Changela

Hariharan

Digavalli

2020

Lecture Notes in Mechanical Engineering

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Mechanical Behavior and Deformation Kinetics of Aluminum Alloys Processed through Cryorolling and Subsequent Annealing

Cited by 18 publications

References 61 publications

Strain‐Hardening Behavior in an AA6060‐T6 Alloy Processed by Equal Channel Angular Pressing

Strain‐Hardening Behavior in an AA6060‐T6 Alloy Processed by Equal Channel Angular Pressing

Re-examination and comparison of activation volume, strain rate sensitivity, and dislocation density for coarse grain and CGP-processed UFG materials

Stress Relaxation Study of Ultrafine-Grained AA 6061 Alloy Processed Through Combined Constrained Groove Pressing and Cold Rolling

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