Effect of Fe on the superplastic deformation of Zn-22 pct Al

Chaudhury, Prabir K.; Park, Kyung‐Tae; Mohamed, Farghalli A.

doi:10.1007/bf02648859

Cited by 44 publications

(58 citation statements)

References 35 publications

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“…Although it has been reported 37,38 that the agreement between the values of the experimental creep rates in region II and those rates predicted from various models represented by Eqn. (1) is not satisfactory, the fact that the concept of boundary sliding accommodated by some form of dislocation motion is successful in predicting the correct stress, temperature and grain size dependencies characterizing region II indicates the significance of boundary sliding as a key element in the process of describing the steady-state process controlling region II.…”

Section: Roles Of Boundaries During Superplastic Deformationmentioning

confidence: 80%

“…Recent creep data reported for several grades of Zn-22%Al containing different levels of impurities, 37,42,43 particularly Fe, have revealed the presence of a threshold stress whose characteristics are consistent with various phenomena associated with boundary segregation, as summarized below:…”

Section: Threshold Stressmentioning

confidence: 83%

“…3(c)]. 37 Experimental evidence suggests that the deformation process controlling region I is not independent of that controlling region II. First, although the interpretation of region I in terms of a new independent deformation process seems to be consistent with some of the mechanical characteristics of this region, the origin and exact nature of such a low-stress process, in view of the high stress exponent (n D 3-5), the high activation energy (Q > Q gb ) and the strong grain size dependence (s ¾ 2) are not clear.…”

Section: Roles Of Boundaries During Superplastic Deformationmentioning

confidence: 98%

“…where P is the shear creep rate, C is a dimensionless constant that can be estimated from the details of each model, 37,38 k is Boltzmann's constant, T is the absolute temperature, D o is the frequency factor for diffusion, G is the shear modulus, b is the Burgers vector, d is the grain size, is the applied shear stress, Q gb is the activation energy for grain boundary diffusion, and r is the gas constant. Although it has been reported 37,38 that the agreement between the values of the experimental creep rates in region II and those rates predicted from various models represented by Eqn.…”

Section: Roles Of Boundaries During Superplastic Deformationmentioning

confidence: 99%

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The role of boundaries during superplastic deformation

Mohamed

2001

Surface & Interface Analysis

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Micrograin superplasticity refers to the ability of fine-grained materials (d < 10 µm, where d is the grain size) to exhibit extensive neck-free elongations during deformation at elevated temperatures (T > 0.5 T m , where T m is the melting point). Consideration of recent experimental data regarding the effects of impurities on the characteristics of micrograin superplasticity reveals an important role played by boundaries in superplastic alloys. This role pertains to the ability of boundaries to serve as favorable sites for the accumulation of impurities, i.e. boundary segregation. Evidence in support of boundary segregation during micrograin superplasticity is reviewed, with particular emphasis on creep behavior, cavitation, ductility, boundary sliding and the formation of cavity stringers.

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Section: Roles Of Boundaries During Superplastic Deformationmentioning

confidence: 80%

Section: Threshold Stressmentioning

confidence: 83%

Section: Roles Of Boundaries During Superplastic Deformationmentioning

confidence: 98%

Section: Roles Of Boundaries During Superplastic Deformationmentioning

confidence: 99%

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The role of boundaries during superplastic deformation

Mohamed

2001

Surface & Interface Analysis

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“…Iron was chosen as the additional element for the following reasons: 1) It has been shown theoretically based on a first-principles approach that Fe will segregate to grain boundaries in Ni 3 Al and will enhance the room temperature cohesive strength of the boundaries [20]; 2) It has been shown that Fe additions to a Zn-22 wt.% Al alloy [21][22][23] segregated to grain boundaries and made these boundaries more resistant to sliding at elevated temperature. It was anticipated that Fe would segregate to grain boundaries in the Cu 6 Sn 5 alloy and would increase their resistance to fracture and thus improve cycle life.…”

Section: Materials Selectionmentioning

confidence: 99%

Cycle Life Enhancement in Cu-Sn Anodes

Wofenstine¹,

Foster²,

Read³

et al. 2002

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This technical report summarizes the work on two different approaches that have been used to increase the cycle life of active-inactive composites in the copper-tin system. The first approach is to reduce the particle size of the active-inactive composities to the nano-scale (<100 nm). The second approach is the addition of extra elements that segregate to grain/phase boundaries and increase the cohesive strength of the boundary. Both approaches significantly improved the capacity retention of a Cu6Sn5 alloy. A larger improvement in capacity retention was exhibited by the addition of 10-wt.% iron compared to the reduction of the particle size to the nano-scale. The volumetric capacity of the Cu6Sn5 alloy containing 10 wt.% iron at 100 cycles is almost three times the theoretical capacity of graphite. The Cu6Sn5-10 wt.% Fe material has potential as a replacement anode for graphite in lithium-ion batteries.

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Creep and Superplasticity: Evolution and Rationalization

Mohamed

2020

Adv Eng Mater

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Detailed studies on the creep behavior of materials are of scientific and practical significance. From a scientific point of view, data obtained from such studies are critical to the characterization of creep behavior in terms of deformation mechanisms. From a practical point of view, information inferred from such studies is useful because of its relevance to many design considerations. Over the past several decades, much progress has been made in rationalizing the creep behavior of metals and solid‐solution alloys. Such progress is extended to understanding the creep behavior of new classes of materials such as powder metallurgy (PM) Al alloys, discontinuous SiC composites, superplastic alloys, and high‐entropy alloys (HEAs). Progress in micrograin superplasticity (1 μm < d < 10 μm, where d is the grain size) has been applied to the emergence of high strain rate (HSR) superplasticity using ultrafine‐grained alloys (0.3 μm < d < 1 μm). The concept of creep is utilized to develop a deformation mechanism for nanocrystalline (nc) materials (d < 100 nm). Using the details of this mechanism, it is possible (1) to explain why the behavior of nc material is not superplastic and 2) to predict a transition from superplastic behavior to nc behavior.

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Effect of Fe on the superplastic deformation of Zn-22 pct Al

Cited by 44 publications

References 35 publications

The role of boundaries during superplastic deformation

The role of boundaries during superplastic deformation

Cycle Life Enhancement in Cu-Sn Anodes

Creep and Superplasticity: Evolution and Rationalization

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