Constitutive equations for the room temperature deformation of commercial purity aluminum

A rational analysis of a number of stress-strain curves for a commercial-purity aluminum has been carried out in order to derive a set of constitutive equations capable of describing the flow stress of the material in terms of the applied strain, rate of straining, and deformation temperature. Such an analysis combines the exponential saturation strain-hardening function earlier proposed by Voce (1948; 1955) with the exponential relationship developed from steady-state creep data at high stresses, and considers the existence of two different regimes of work-hardening. The proposed formalism requires only the use of seven material constants which include the temperature-dependent shear modulus, the activation energy for self-diffusion, one pre-exponential factor, and four stress sensitivity parameters of the strain rate. A satisfactory correlation has been obtained between the experimental values of the flow stress and those predicted for the model, which enables it to be used in conjunction with any algorithm based on finite differences methods or finite elements codes to simulate hot-working operations carried out in this material.

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Effect of the Rate of Multiaxial Compression at Room Temperature on the Evolution of Microstructure of Commercial-Purity Aluminum

Metal Science and Heat Treatment ◽

10.1007/s11041-019-00382-6 ◽

2019 ◽

Vol 61 (1-2) ◽

pp. 96-100

Author(s):

Y. Yang ◽

S. J. Yang ◽

Z. Wang ◽

X. F. Gao

Keyword(s):

Room Temperature ◽

Commercial Purity ◽

Multiaxial Compression ◽

Commercial Purity Aluminum ◽

Evolution Of Microstructure

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Room-temperature deformation of single crystals of ZrB2 and TiB2 with the hexagonal AlB2 structure investigated by micropillar compression

Scientific Reports ◽

10.1038/s41598-021-93693-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zhenghao Chen ◽

Bhaskar Paul ◽

Sanjib Majumdar ◽

Norihiko L. Okamoto ◽

Kyosuke Kishida ◽

...

Keyword(s):

Single Crystals ◽

Plastic Flow ◽

Room Temperature ◽

Resolve Shear Stress ◽

Temperature Deformation ◽

Slip Systems ◽

Compression Tests ◽

Plastic Deformation Behavior ◽

Bulk Single Crystals ◽

Micropillar Compression

AbstractThe plastic deformation behavior of single crystals of two transition-metal diborides, ZrB2 and TiB2 with the AlB2 structure has been investigated at room temperature as a function of crystal orientation and specimen size by micropillar compression tests. Although plastic flow is not observed at all for their bulk single crystals at room temperature, plastic flow is successfully observed at room temperature by the operation of slip on {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 3> in ZrB2 and by the operation of slip on {1$${\bar{1}}$$ 1 ¯ 00}<0001> and {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 0> in TiB2. Critical resolve shear stress values at room temperature are very high, exceeding 1 GPa for all observed slip systems; 3.01 GPa for {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 3> slip in ZrB2 and 1.72 GPa and 5.17 GPa, respectively for {1$${\bar{1}}$$ 1 ¯ 00}<0001> and {1$${\bar{1}}$$ 1 ¯ 00}<11$${\bar{2}}$$ 2 ¯ 0> slip in TiB2. The identified operative slip systems and their CRSS values are discussed in comparison with those identified in the corresponding bulk single crystals at high temperatures and those inferred from micro-hardness anisotropy in the early studies.

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