Effect of Nb<sup>5+</sup>substitution on the piezoelectric properties of PLZT ceramics

The isothermal hot compression tests of 43CrNi steel was carried out at temperatures 800°C to 1 050°C at an interval of 50°C and at constant strain rates of 0.01, 0.1, 1.0 and 10 s − 1 for total true strain of 0.7. The values of experimental stress were corrected for adiabatic heating which was used for flow stress modeling, and further its predictability was verified with experimental results. The true stress-true strain curves exhibit peak stresses followed by softening due to occurrence of DRX. The activation energy was calculated based on sinh type equation and found to be increasing with increase in strain. The obtained stress exponent 5.4, suggests that the mechanism of hot deformation is dislocation glide controlled by dislocation climb. Strain rate sensitivity maps and processing maps were developed using dynamic materials model (DMM), modified DMM with different instability criteria. The instability parameter, κ j , is directly related to the dissipative function which is associated to microstructural changes, J, whereas the instability parameters, ξ and κ, are associated with the strain rate sensitivity parameter, m. Therefore, the instability parameter, κ j , is more mathematically precise as it eliminates m from its calculations. The microstructures of deformed specimens were studied and correlated with the domains of processing maps to validate the workability region.KEY WORDS: medium carbon low alloy steel; processing maps; hot deformation; constitutive analysis; thermo mechanical simulator.

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“…The efficiency and instability parameter (κ) of modified DMM is given by Murty et al without considering the power law, and are given as: 11) …”

Section: Modified Dynamic Materials Modelmentioning

confidence: 99%

Modelling of Flow Stress and Prediction of Workability by Processing Map for Hot Compression of 43CrNi Steel

Kumar

Rajput

et al. 2017

ISIJ International

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“…When used donor dopants we obtain so called "soft" PZT materials and when used acceptor dopants we obtain so called "hard" PZT materials. The term "soft" respectively the term "hard" refers to the polarization and depolarization behaviour [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Dopants on the Properties of Lead Zirconate Titanate System

Dumitru,

Ion,

Clicinschi

et al. 2023

Scientific Bulletin of Valahia University - Materials and Mechanics

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The doped Pb(Zr0.52Ti0.48)O3 system with Nb5+ and Sr2+ were obtained by solid state reactions. The influence of nature of dopants on structural and microstructural properties were analyzed by XRD and SEM techniques and were also investigated the obtained dielectric and piezoelectric properties. The XRD analyzes and the SEM images highlighted the obtaining of homogeneous tetragonal structures, of the perovskite type. The physical (ρa), dielectric constant (ɛr) and piezoelectric (kp) properties of the doped PZT systems were investigated. The Nb5+ doped Pb(Zr0.52Ti0.48)O3 system presented the ɛr = 488 and kp = 0,52. Sr2+ substitution for Nb5+ doped Pb(Zr0.52Ti0.48)O3 reduced the Curie temperature (from 420°C to 360°C), increased the dielectric constant at 1180, and also decreasing the kp (0,39).

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Impedance spectroscopy studies on Ga‐ion‐modified PLZT ceramics

Dutta¹,

Choudhary

Sinha

2005

Physica Status Solidi (a)

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Polycrystalline samples of [Pb0.92(La1–zGaz)0.08][Zr0.65Ti0.35]0.98O3 (PLGZT) for z = 0.0, 0.3, 0.6, 0.9, and 1.0 were prepared by a solid‐state reaction technique. The single‐phase formation of the new compounds with tetragonal crystal structures was established by the room‐temperature X‐ray analysis. The occupancy of Ga ion in the La site has been confirmed by FTIR analysis. Complex impedance spectroscopy (CIS) has provided a convincing evidence for the existence of both grain (bulk) and grain boundary effects in the materials, which is also evident from the microstructures, comprise grains separated by well‐defined boundaries. The electrical processes in the sample have been modeled in the form of an electrical equivalent circuit made up of a series combination of two parallel RC circuits attributed to grains and grain boundaries. The real and imaginary parts of dielectric constants have been separated from impedance spectrum results and expressed in terms of loss tangent (tan δ). The ferroelectric transition temperature (Tc) of the materials is evaluated from the plot of real permittivity versus temperature and found to be shifted to higher temperature side with increasing Ga‐ion concentration. A sharp rise in conductivity is observed in the nature of temperature variation of the bulk electrical conductivity (σdc) at higher temperature for all the Ga‐modified PLZT samples. This type of behavior is typical to dielectric ceramics having conductive grain boundary arising out of a relaxation process of the Maxwell–Wagner type. At higher temperature a substantial increase in conductivity ∼10–3 S cm–1 is achieved for complete replacement of the La ion by Ga (z = 1.0). (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Effect of Nb⁵⁺substitution on the piezoelectric properties of PLZT ceramics

Cited by 16 publications

References 8 publications

Modelling of Flow Stress and Prediction of Workability by Processing Map for Hot Compression of 43CrNi Steel

Modelling of Flow Stress and Prediction of Workability by Processing Map for Hot Compression of 43CrNi Steel

The Influence of the Dopants on the Properties of Lead Zirconate Titanate System

Impedance spectroscopy studies on Ga‐ion‐modified PLZT ceramics

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Effect of Nb5+substitution on the piezoelectric properties of PLZT ceramics

Cited by 16 publications

References 8 publications

Modelling of Flow Stress and Prediction of Workability by Processing Map for Hot Compression of 43CrNi Steel

Modelling of Flow Stress and Prediction of Workability by Processing Map for Hot Compression of 43CrNi Steel

The Influence of the Dopants on the Properties of Lead Zirconate Titanate System

Impedance spectroscopy studies on Ga‐ion‐modified PLZT ceramics

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Product

Resources

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Effect of Nb⁵⁺substitution on the piezoelectric properties of PLZT ceramics