Cyclic plasticity experiments and polycrystal plasticity modeling of three distinct Ti alloy microstructures

Smith, Benjamin D.; Shih, Donald S.; McDowell, David L.

doi:10.1016/j.ijplas.2013.10.004

Cited by 74 publications

(21 citation statements)

References 46 publications

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“…A single colony has uniform α and β crystal orientations with alternating α and β lamella. We found similar results to those reported by Smith et al [9], which includes a strong basal texture along the axis of the rod, an average α-lamellae thickness of 3 µm, a mean colony size of 165 µm, and an α-phase volume fraction of 98%. Samples were sectioned and mechanically polished.…”

Section: Methodssupporting

confidence: 91%

“…Microstructure sensitive models are critically needed to aid in the development of new, stronger, more fatigue resistant titanium alloys [3][4][5][6][7] and understand the relationships between microstructure and properties. These models (e.g., [8][9][10][11][12]) rely on experiments for parameter calibration. Typically, the process utilizes bulk mechanical tests (e.g., uniaxial tension and compression tests).…”

Section: Introductionmentioning

confidence: 99%

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Mechanical characterization of Ti-6Al-4V titanium alloy at multiple length scales using spherical indentation stress-strain measurements

Weaver

Kalidindi

2016

Materials & Design

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Recent advances in spherical indentation stress-strain protocols and analyses have demonstrated the capability for measuring reliably the local mechanical responses in polycrystalline metal samples at different length scales, ranging from sub-micron (regions within individual grains) to several hundreds of microns (regions covering several grains). These recent advances have now made it possible to study systematically the mechanical behavior of a single material system at different length scales, with tremendous potential to obtain new insights into the role of individual phases, interfaces, and other microscale constituents on the macroscale mechanical response of the material. In this paper, we report spherical indentation stress-strain measurements with different indenter sizes (microns to millimeters) on Ti-6Al-4V (Ti-64) which capture the mechanical response of single phase alpha-Ti-64, single colony (alpha-beta), few colonies, and many colonies of Ti-64. The results show that the average mechanical response (indentation modulus and yield strength) from multiple indentations remains relatively unchanged from single phase alpha to many colonies of Ti-64, while the variance in the response decreases with indenter size. The work-hardening response in indentation tests follows a similar

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Section: Methodssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Mechanical characterization of Ti-6Al-4V titanium alloy at multiple length scales using spherical indentation stress-strain measurements

Weaver

Kalidindi

2016

Materials & Design

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“…The combination of each MVE and its associated properties constitutes one data point for the desired S-P linkages. The crystal plasticity framework used here was developed in prior work for α-phase grains in Ti6-4[66,[96][97][98][99][100][101][102]. The model parameters relevant to the predictions of the effective (bulk) elastic stiffness and yield strength are summarized inTable 1.…”

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confidence: 99%

Reduced-order structure-property linkages for polycrystalline microstructures based on 2-point statistics

et al. 2017

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Computationally efficient structure-property (S-P) linkages (i.e., reduced order models) are a necessary key ingredient in accelerating the rate of development and deployment of structural materials. This need represents a major challenge for polycrystalline materials, which exhibit rich heterogeneous microstructure at multiple structure/length scales, and exhibit a wide range of properties. In this study, a novel framework is described for extracting S-P linkages in polycrystalline microstructures that are obtained using 2-point spatial correlations (also called 2-point statistics) to quantify the material's microstructure, and principal component analysis (PCA) to represent this information in a reduced dimensional space. Additionally, it is demonstrated that the use of generalized spherical harmonics (GSH) as a Fourier basis for functions defined on the orientation space leads to a compact and computationally efficient representation of the desired S-P linkages. In this study, these novel protocols are developed and demonstrated for elastic stiffness and yield strength predictions for α−Ti microstructures using a dataset produced through microscale finite element simulations.

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“…Several studies have been undertaken to link micro-macro properties of metals (Barbe et al, 2001;Dunne et al, 2007;Zhang et al, 2007Zhang et al, , 2016Guilhem et al, 2018), but how local properties affect macroscopic properties is still not fully understood. In particular, the behavior of metallic materials 5 under cyclic loading conditions is the subject of considerable attention (Ghorbanpour et al, 2017;Smith et al, 2018;Yu et al, 2013). The present paper explores two topics, namely ratcheting and mean stress relaxation in polycrystalline aggregates under cyclic loading.…”

Section: Introductionmentioning

confidence: 98%

Crystal plasticity modeling of the cyclic behavior of polycrystalline aggregates under non-symmetric uniaxial loading: Global and local analyses

Farooq

Cailletaud

Forest

et al. 2020

International Journal of Plasticity

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When a sample is cyclically loaded under a mean stress or strain, incremental strain ratcheting or mean stress relaxation phenomena are usually observed. Experiments show that for metallic materials there is generally no full mean stress relaxation as well as saturation of macroscopic strain ratcheting. In contrast, most macroscopic constitutive models produce both quantities in excess, and complex sets of additional internal variables must be introduced to improve the modeling. Little attention has been paid to model such phenomena using polycrystal aggregates especially going up to the regime of cyclic mechanical stability. In this work based on an elementary crystal plasticity model for FCC crystals and large scale finite element, it is be shown that the interaction between different grains is sufficient to cater for such complex phenomena. Light is shed on how different regions of the polycrystal accommodate each other and how the classical definition of constant rate strain ratcheting or a zero mean stress is nearly impossible to apply to a polycrystalline aggregate. In addition, it is shown that even if a macroscopic stable hysteresis stress strain loop is observed, ratcheting phenomena can still be observed at the local scale. The distributions of different constitutive quantities within a polycrystal are also analyzed which gives a new insight into what is happening inside a polycrystal in terms of stress and strain redistribution. In particular, the existence of evolving bimodal distributions of stress and accumulated plastic strain is evidenced and related to the occurrence of plastic shakedown and incomplete mean stress relaxation. Two numerical criteria to detect strain ratcheting are finally proposed and discussed. Kang et al., 2010). Mean stress in this article is defined as (Σ max + Σ min )/2 where Σ max and Σ min are the 15 maximum and minimum applied stresses in a cyclically loaded component. The stress amplitude is defined as Σ max −Σ min /2. With regards to asymetric strain controlled cyclic loadings, it is also known that under a given stress amplitude, increasing the mean stress, or increasing the applied mean stress under constant amplitude, both increase the rate of ratcheting (Goodman, 1984). On the other hand, experimental observations indicate levels of mean stress for which there is very low ratcheting and the mechanical state of the material converges 20 towards plastic shakedown (Pellissier-Tanon et al., 1982). Similarly, for asymmetric strain controlled loading conditions, a cyclic mean stress is observed, and several experimental studies (Wehner and Fatemi, 1991;Nikulin et al., 2019;Prithivirajan and Sangid, 2018) have deciphered the corresponding physical mechanisms. These observations show that for a given positive mean strain, and a low strain amplitude, the mean stress does not completely relax to zero. Also, increasing the strain amplitude leads to a nonlinear decrease of the 25

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Cyclic plasticity experiments and polycrystal plasticity modeling of three distinct Ti alloy microstructures

Cited by 74 publications

References 46 publications

Mechanical characterization of Ti-6Al-4V titanium alloy at multiple length scales using spherical indentation stress-strain measurements

Mechanical characterization of Ti-6Al-4V titanium alloy at multiple length scales using spherical indentation stress-strain measurements

Reduced-order structure-property linkages for polycrystalline microstructures based on 2-point statistics

Crystal plasticity modeling of the cyclic behavior of polycrystalline aggregates under non-symmetric uniaxial loading: Global and local analyses

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