An Investigation of the Mechanical Behavior of a Superplastic Yttria-Stabilized Zirconia

1990 ◽  
Vol 196 ◽  
Author(s):  
Yan Ma ◽  
Terence G. Langdon
Keyword(s):  
Strain Rate ◽  
Mechanical Behavior ◽  
Mechanical Characteristics ◽  
Elevated Temperatures ◽  
Tensile Axis ◽  
Tetragonal Zirconia ◽  
Yttria Stabilized Zirconia ◽  
Strain Rates ◽  
Stabilized Zirconia ◽  
Internal Cavities

ABSTRACTExperiments were conducted to determine the mechanical characteristics of an yttria-stabilized tetragonal zirconia containing 3 mol % Y2O3. Specimens were pulled in tension at elevated temperatures over a range of strain rates. It is demonstrated that this material exhibits good superplastic ductility, with tensile elongations >100% when the tests are conducted at low strain rates. Internal cavities are formed during deformation and it is shown that the cavitated area decreases with decreasing strain rate. At fast strain rates, of the order of 10−3 s−1, the cavities tend to link preferentially in a direction perpendicular to the tensile axis.

scholarly journals Extension of Flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect

2020 ◽  
Author(s):  
Chuang Liu ◽  
Dongzhi Sun ◽  
Xianfeng Zhang ◽  
Florence Andrieux ◽  
Tobias Gerster
Keyword(s):  
Cast Iron ◽  
Constitutive Model ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Damage Model ◽  
Iron Alloys ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Damage Models ◽  
Rate Dependent

Abstract Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry. To study the mechanical behavior of a typical ductile cast iron (GJS-450) with nodular graphite, uni-axial quasi-static and dynamic tensile tests at strain rates of 10− 4, 1, 10, 100, and 250 s− 1 were carried out. In order to investigate the effects of stress state, specimens with various geometries were used in the experiments. Stress–strain curves and fracture strains of the GJS-450 alloy in the strain-rate range of 10− 4 to 250 s− 1 were obtained. A strain rate-dependent plastic flow law based on the Voce model is proposed to describe the mechanical behavior in the corresponding strain-rate range. The deformation behavior at various strain rates is observed and analyzed through simulations with the proposed strain rate-dependent constitutive model. The available damage model from Bai and Wierzbicki is extended to take the strain rate into account and calibrated based on the analysis of local fracture strains. The validity of the proposed constitutive model including the damage model was verified by the corresponding experimental results. The results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 alloys. The predictions with the proposed constitutive model and damage models at various strain rates agree well with the experimental results, which illustrates that the rate-dependent flow rule and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain rates.

Strain rate effects on the mechanical behavior of single-lap glass/carbon nanofiber/epoxy composite bolted joints

2020 ◽  
Vol 54 (30) ◽  
pp. 4807-4819 ◽  
Author(s):  
AR Shamaei-Kashani ◽  
MM Shokrieh
Keyword(s):  
Strain Rate ◽  
Mechanical Behavior ◽  
Epoxy Composite ◽  
Bolted Joints ◽  
Dynamic Strain ◽  
Experimental Program ◽  
Strain Rates ◽  
Mechanical Parameters ◽  
Damage Initiation ◽  
Bearing Strength

In the present research, effects of applying strain rate on the mechanical behavior of single-lap glass/CNF/epoxy composite bolted joints including, damage initiation bearing stress, 2% offset bearing strength, ultimate bearing strength, bearing chord stiffness, ultimate bearing strain, and energy absorption were studied. To this end, a comprehensive experimental program was conducted. The protruding head bolt was used, the clearance was considered to be near fit and a finger-tight bolt condition was applied to all joints. The dimensions of joints were chosen to promote the bearing failure mode based on the ASTM standard. Four types of single-lap bolted joints (SLJs) with lay-ups of [–45/0/45/90]s and [90/–452/45]s with and without CNFs were tested at strain rates in the range of 0.0048 s−1 to 0.89 s−1. Unlike the available experimental results, the results obtained by the present experiments showed that the strain rate has a significant effect on all the above-mentioned mechanical parameters of SLJs. Also, it was shown that employing CNFs improved the mechanical parameters of SLJs under quasi-static and dynamic strain rates.

In vitro evaluation of an yttria-stabilized zirconia reinforced nano-hydroxyapatite/polyamide 66 ternary biomaterial: biomechanics, biocompatibility and bioactivity

RSC Advances ◽  
2016 ◽  
Vol 6 (115) ◽  
pp. 114086-114095 ◽  
Author(s):  
Yuling Li ◽  
Hong Li ◽  
Jing Zhang ◽  
Weikang Zhao ◽  
Jieliang Shen ◽  
...  
Keyword(s):  
Tetragonal Zirconia ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Polyamide 66 ◽  
In Vitro Evaluation

The characterization of a novel ternary biomaterial composed of nano-hydroxyapatite/polyamide 66/yttria-stabilized tetragonal zirconia.

scholarly journals Dynamic Mechanical Characteristics and Constitutive Modeling of Rail Steel over a Wide Range of Temperatures and Strain Rates

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Peijie Liu ◽  
Yanming Quan ◽  
Guo Ding
Keyword(s):  
Strain Rate ◽  
Mechanical Behavior ◽  
Split Hopkinson Pressure Bar ◽  
Rail Steel ◽  
Strain Rates ◽  
Dynamic Mechanical ◽  
Flow Response ◽  
Strain And Strain Rate ◽  
Average Absolute Relative Error ◽  
Wide Range

Rail steel plays an indispensable role in the safety and stability of the railway system. Therefore, a suitable constitutive model is quite significant to understand the mechanical behavior of this material. Here, the compressive mechanical behavior of heat-treated U71Mn rail steel over a wide range of strain rates (0.001 s−1–10000 s−1) and temperatures (20°C–800°C) was systematically investigated via uniaxial quasistatic and dynamic tests. The split Hopkinson pressure bar (SHPB) apparatus was utilized to perform dynamic mechanical tests. The effects of temperature, strain, and strain rate on the dynamic compressive characteristics of U71Mn were discussed, respectively. The results indicate that the flow response of U71Mn is both temperature-sensitive and strain rate-sensitive. However, the influence of temperature on the flow response is more remarkable than that of strain rate. On the basis of the experimental data, the original and modified Johnson-Cook (JC) models of the studied material were established, respectively. Using correlation coefficient and average absolute relative error parameters, it is revealed that better agreement between the experimental and predicted stress is reached by the modified JC model, which demonstrates that the modified one can characterize the mechanical behavior of the studied material preferably.

Thermal Cycling Effect on Mechanical Properties of Yttria-Stabilized Tetragonal Zirconia

2013 ◽  
Vol 538 ◽  
pp. 121-124
Author(s):  
Jing Zhang
Keyword(s):  
Mechanical Properties ◽  
Phase Transition ◽  
Thermal Expansion ◽  
Flexural Strength ◽  
Thermal Cycling ◽  
Tetragonal Zirconia ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Optical Applications ◽  
The Stability

Yttria-stabilized zirconia (YSZ) is an important material in the area of energy and optical applications. In this study, the mechanical properties (Young’s modulus, Vickers hardness, flexural strength, and coefficient thermal expansion) and physical properties (phase transition) of yttria-stabilized tetragonal zirconia polycrystalline (Y-TZP) was reported. The effect of thermal cycling on the mechanical properties and the stability was also evaluated.

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