Role of indenter angle on the plastic deformation underneath a sharp indenter and on representative strains: An experimental and numerical study

Prasad, K. Eswar; Chollacoop, Nuwong; Ramamurty, Upadrasta

doi:10.1016/j.actamat.2011.03.058

Cited by 36 publications

(13 citation statements)

References 57 publications

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“…In this regard, the heterogeneous deformation in indentation gives rise to dislocation density gradients in the plastic zone. These gradients can be indirectly visualized through either localized measurement of strength (via hardness) [8][9][10] or the rate dependence of surface topography in metallographic etching [11,12] and microstructure in static/dynamic recrystallization [13]. Hardness measurement has been used to estimate strain contours through empirically derived relationships between strain and hardness in controlled compression testing [9].…”

Section: Introductionmentioning

confidence: 99%

Deformation field heterogeneity in punch indentation

et al. 2014

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Plastic heterogeneity in indentation is fundamental for understanding mechanics of hardness testing and impression-based deformation processing methods. The heterogeneous deformation underlying plane-strain indentation was investigated in plastic loading of copper by a flat punch. Deformation parameters were measured, in situ, by tracking the motion of asperities in high-speed optical imaging. These measurements were coupled with multi-scale analyses of strength, microstructure and crystallographic texture in the vicinity of the indentation. Self-consistency is demonstrated in description of the deformation field using the in situ mechanics-based measurements and post-mortem materials characterization. Salient features of the punch indentation process elucidated include, among others, the presence of a dead-metal zone underneath the indenter, regions of intense strain rate (e.g. slip lines) and extent of the plastic flow field. Perhaps more intriguing are the transitions between shear-type and compression-type deformation modes over the indentation region that were quantified by the highresolution crystallographic texture measurements.

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Section: Introductionmentioning

confidence: 99%

Deformation field heterogeneity in punch indentation

et al. 2014

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“…The FE simulation data on Constraint Factor for Ti64 as a function of temperature taken from current research has been compared with Expansion Cavity Model (ECM) and Fully Plastic Model (FPM) [15][16][17][18]. In Figure 11, line 1 represents Constraint Factor values calculated from the ECM considering σ f in the place of σ y as a function of the normalised strain 'B', line 2 represents Constraint Factor values in fully-plastic (FP) condition as given FP Model and the FE simulation data for Ti64 taken from the present work pertaining to temperatures 300K to 673K is shown in Figure 11.…”

Section: Comparison Of Constraint Factor With Theoretical Modelsmentioning

confidence: 99%

Temperature dependence of indentation behavior of Ti-6Al-4V alloy for bio medical applications

2019

Biointerface Res Appl Chem

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Numerical analysis of spherical indentation was carried out to study temperature dependence (300-673K) of elasto-plastic deformation behavior of Ti-6Al-4V alloy. Flow stress and strain hardening exponent ‘n’ were determined from load versus indenter penetration depth profiles generated through FE model using Dao’s reverse analysis approach. The upward flow around the residual impression as a function of average strain, which describes the strain hardening behaviour of the alloys was also investigated. The simulated values of CF have been used to predict high strain-rate plastic flow behavior considering indentation data. It was observed that there is a good correlation between data from simulation and experimental results in the literature. The FE model developed in the current investigation can be used for simulating the flow behavior of Ti-6Al-4V alloy. The temperature dependent CF value in the fully plastic regime from the current study is approximately 2.69 against experimentally evaluated value of 2.95. Meyer’s hardness is generally high due to the presence of cold layer resulting from grinding and polishing of the test specimen. Absence of such effects in simulation of spherical indentation resulted in reduced value of CF.

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“…3) The behavior of the latter has been later confirmed by finite element analysis. 19) It should be noted that all the above mentioned studies referred to the unloading stage and that the observed ellipticity was related to the recovered structure, which is known to be governed by the Young modulus rather than yield stress.…”

Section: Introductionmentioning

confidence: 98%

“…3,9,10,13,14,1719) However, in most of these studies, the outer iso-strain boundaries were elliptical, rather than hemispherical, with the long axis coinciding with the loading direction. 3,14,19,28) Ellipticity has been found to decrease markedly in AA7075 as the yield stress and strain hardening coefficient increase. 3) The behavior of the latter has been later confirmed by finite element analysis.…”

Section: Introductionmentioning

confidence: 99%

Determination of the Yield Radius and Yield Stress in 2198-T3 Aluminum Alloy by Means of the Dual-Scale Instrumented Indentation Test

Pero

Maizza²,

Marco

et al. 2019

Mater. Trans.

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A new dual-scale instrumented indentation test (DualS-IIT) methodology is here proposed to determine the yield stress (in a tensile-like sense). The methodology involves measuring the bulk yield radius, as defined by the expansion cavity model (ECM), induced by a Vickers macro-indentation in a medium plane cross-section. The bulk yield radius is measured by means of a subsurface nano-hardness survey along the load direction in correspondence to the transition interface between the hemispherical strain hardened region and the surrounding elastic region. The methodology has been applied to an AlLi (A2198-T3) alloy and a yield stress of 297 MPa has been measured (in agreement with a tensile test); moreover, anomalous plastic deformation behaviour has appeared under indentation. The combination of macro-and nano-indentation tests in one single experiment, as in the proposed methodology, offers a unique experimental basis to directly correlate the mechanical properties of a material at two different scales, which at present is an open issue in the research on indentation.

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Role of indenter angle on the plastic deformation underneath a sharp indenter and on representative strains: An experimental and numerical study

Cited by 36 publications

References 57 publications

Deformation field heterogeneity in punch indentation

Deformation field heterogeneity in punch indentation

Temperature dependence of indentation behavior of Ti-6Al-4V alloy for bio medical applications

Determination of the Yield Radius and Yield Stress in 2198-T3 Aluminum Alloy by Means of the Dual-Scale Instrumented Indentation Test

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