The Experts below are selected from a list of 312 Experts worldwide ranked by ideXlab platform
Qiang Sun - One of the best experts on this subject based on the ideXlab platform.
-
theoretical estimation to the cyclic strength coefficient and the cyclic strain Hardening Exponent for metallic materials preliminary study
Journal of Materials Engineering and Performance, 2009Co-Authors: Zhongping Zhang, Yanjiang Qiao, Qiang SunAbstract:The ultimate purpose of the present article is to theoretically estimate the cyclic strength coefficient and the cyclic strain-Hardening Exponent. For this purpose, the performance parameters of 22 alloys were examined and equations that relate the cyclic strength coefficient and the cyclic strain-Hardening Exponent to the monotonic tensile ones were developed. Then, by using formulas that express the strength coefficient and the strain-Hardening Exponent through the four conventional tensile performance parameters, i.e., the yield strength, the ultimate tensile strength, the fracture strength, and the fracture ductility, expressions that describe the cyclic strength coefficient and the cyclic strain-Hardening Exponent are established. By means of cyclic stress-strain curve, the limitations of the traditional methods of estimating the cyclic strength coefficient and the cyclic strain-Hardening Exponent are pointed out, and the ability of the new equations at describing the process are established. From the equations the cyclic strength coefficient and the cyclic strain-Hardening Exponent can be theoretically estimated using the monotonic ones. Furthermore, in the absence of the strength coefficient and the strain-Hardening Exponent, the cyclic ones can still be obtained from the expressions using the four conventional tensile performance parameters.
-
formula relating fracture strength and fracture ductility with strength coefficient and strain Hardening Exponent
Journal of Materials Engineering and Performance, 2006Co-Authors: Zhongping Zhang, Qiang Sun, Yanjian Qiao, Wenzhen ZhaoAbstract:To theoretically calculate the strength coefficient and the strain-Hardening Exponent with conventional mechanical property parameters, formulas relating them with fracture strength and fracture ductility are studied using test data for ten alloys. The applicability of the traditional formula relating these four material constants is discussed first, and then new formulas are proposed based on the premise that the traditional approach cannot be used. The main conclusions made herein are that only under certain conditions can be traditional formula be used to describe the relationship among fracture strength, fracture ductility, strength coefficient, and strain-Hardening Exponent; otherwise, a new formula must be used.
-
theoretical calculation of the strain Hardening Exponent and the strength coefficient of metallic materials
Journal of Materials Engineering and Performance, 2006Co-Authors: Zhongping Zhang, Wenzhen Zhao, Qiang SunAbstract:The purpose of the present article is to theoretically calculate the strain-Hardening Exponent and the strength coefficient of metallic materials. For this purpose, two equations are used. The first one correlates the strain-Hardening Exponent and the strength coefficient with the yield stress-strain behavior, while the other one correlates the fracture strength and the fracture ductility. From these two equations, the expressions of both the strain-Hardening Exponent and the strength coefficient are deduced. Theoretical results from the deduced expressions are then compared with test data. Through the comparison of equations and data, if adequate test data are lacking, the deduced expressions can be used to theoretically calculate the strain-Hardening Exponent and the strength coefficient for metallic materials. The characteristics of the theoretical approach are simple and easy to use. In addition, the theoretical results can be further applied to examine the correctness of the test data.
Zhongping Zhang - One of the best experts on this subject based on the ideXlab platform.
-
theoretical estimation to the cyclic strength coefficient and the cyclic strain Hardening Exponent for metallic materials preliminary study
Journal of Materials Engineering and Performance, 2009Co-Authors: Zhongping Zhang, Yanjiang Qiao, Qiang SunAbstract:The ultimate purpose of the present article is to theoretically estimate the cyclic strength coefficient and the cyclic strain-Hardening Exponent. For this purpose, the performance parameters of 22 alloys were examined and equations that relate the cyclic strength coefficient and the cyclic strain-Hardening Exponent to the monotonic tensile ones were developed. Then, by using formulas that express the strength coefficient and the strain-Hardening Exponent through the four conventional tensile performance parameters, i.e., the yield strength, the ultimate tensile strength, the fracture strength, and the fracture ductility, expressions that describe the cyclic strength coefficient and the cyclic strain-Hardening Exponent are established. By means of cyclic stress-strain curve, the limitations of the traditional methods of estimating the cyclic strength coefficient and the cyclic strain-Hardening Exponent are pointed out, and the ability of the new equations at describing the process are established. From the equations the cyclic strength coefficient and the cyclic strain-Hardening Exponent can be theoretically estimated using the monotonic ones. Furthermore, in the absence of the strength coefficient and the strain-Hardening Exponent, the cyclic ones can still be obtained from the expressions using the four conventional tensile performance parameters.
-
formula relating fracture strength and fracture ductility with strength coefficient and strain Hardening Exponent
Journal of Materials Engineering and Performance, 2006Co-Authors: Zhongping Zhang, Qiang Sun, Yanjian Qiao, Wenzhen ZhaoAbstract:To theoretically calculate the strength coefficient and the strain-Hardening Exponent with conventional mechanical property parameters, formulas relating them with fracture strength and fracture ductility are studied using test data for ten alloys. The applicability of the traditional formula relating these four material constants is discussed first, and then new formulas are proposed based on the premise that the traditional approach cannot be used. The main conclusions made herein are that only under certain conditions can be traditional formula be used to describe the relationship among fracture strength, fracture ductility, strength coefficient, and strain-Hardening Exponent; otherwise, a new formula must be used.
-
theoretical calculation of the strain Hardening Exponent and the strength coefficient of metallic materials
Journal of Materials Engineering and Performance, 2006Co-Authors: Zhongping Zhang, Wenzhen Zhao, Qiang SunAbstract:The purpose of the present article is to theoretically calculate the strain-Hardening Exponent and the strength coefficient of metallic materials. For this purpose, two equations are used. The first one correlates the strain-Hardening Exponent and the strength coefficient with the yield stress-strain behavior, while the other one correlates the fracture strength and the fracture ductility. From these two equations, the expressions of both the strain-Hardening Exponent and the strength coefficient are deduced. Theoretical results from the deduced expressions are then compared with test data. Through the comparison of equations and data, if adequate test data are lacking, the deduced expressions can be used to theoretically calculate the strain-Hardening Exponent and the strength coefficient for metallic materials. The characteristics of the theoretical approach are simple and easy to use. In addition, the theoretical results can be further applied to examine the correctness of the test data.
Dongil Kwon - One of the best experts on this subject based on the ideXlab platform.
-
determination of tensile properties by instrumented indentation technique representative stress and strain approach
Surface & Coatings Technology, 2006Co-Authors: Juyoung Kim, Kyungwoo Lee, Jungsuk Lee, Dongil KwonAbstract:Tensile properties can be evaluated by defining representative stress and strain with the parameters obtained from instrumented indentation tests using a spherical indenter. The accuracy of this approach depends strongly on how the contact depth is analyzed and how the representative stress and strain are defined. The primary factors influencing the determination of contact depth, pile-up/sink-in and elastic deflection, were quantified by analyzing indentation morphology by finite element simulation; then plastic pile-up/sink-in behavior was formulated in terms of the strain-Hardening Exponent and the ratio of indentation depth to indenter radius. For the representative strain, the definition by tangent function was determined to be more appropriate for assessing tensile properties based on derived behaviors of the strain-Hardening Exponent. This approach was experimentally verified by comparing tensile properties of 10 metallic materials from uniaxial tensile tests and instrumented indentation tests.
-
instrumented microindentation studies on long term aged materials work Hardening Exponent and yield ratio as new degradation indicators
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2005Co-Authors: Jaeil Jang, Yeol Choi, Yunhee Lee, Dongil KwonAbstract:Abstract Using an instrumented microindentation technique for evaluating tensile properties, the present study was undertaken to determine new mechanical parameters measurable in the field that can indicate time-dependent material degradation. Lab-scale tests performed on a Cr–Ni steel and a Cr–Mo steel, two of the most popular heat-resistant steels for facilities in petrochemical and power plants, showed that the work-Hardening Exponent and yield ratio could be useful as mechanical parameters indicating degradation. The in-field applicability of these parameters was partly verified.
M Q Li - One of the best experts on this subject based on the ideXlab platform.
-
strain rate sensitivity and strain Hardening Exponent during the isothermal compression of ti60 alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2012Co-Authors: M Q LiAbstract:Abstract In this paper, the flow stress was investigated in detail during the isothermal compression of Ti60 alloy. The strain rate sensitivity and the strain Hardening Exponent of Ti60 alloy were calculated based on the flow stress–strain curves. The results showed that the softening effect in the α + β two-phase region was more significant than that in the β single-phase region due to the change in the deformation heat of the alloy. An initial yield drop was observed at or above 1273 K and in the strain rate range of 0.1–10.0 s −1 . The β phase became the continuous phase above 1273 K, which led to little temperature dependence of flow stress. The maximum m value of 0.34 occurred at 1253 K and a strain rate of 0.001 s −1 during the isothermal compression of Ti60 alloy. The strain rate sensitivity at a strain of 0.7 and a strain rate of 10.0 s −1 decreased with increasing deformation temperature after a peak value. And the m values decreased with increasing strain rate. This phenomenon could be reasonably explained based on the microstructure evolution during the isothermal compression of Ti60 alloy. The strain Hardening Exponent increased with increasing deformation temperature at the strain rates of 0.001 s −1 , 1.0 s −1 and 10.0 s −1 . The variation of strain Hardening Exponent with strain was observed to be dependent on the strain rate and the deformation temperature.
-
the variation of strain rate sensitivity Exponent and strain Hardening Exponent in isothermal compression of ti 6al 4v alloy
Materials & Design, 2010Co-Authors: M Q Li, Weixin Yu, Hong LiAbstract:Abstract The deformation behavior in isothermal compression of Ti–6Al–4V alloy is investigated in the deformation temperatures ranging from 1093 K to 1303 K, the strain rates ranging from 0.001 s −1 to 10.0 s −1 at an interval of an order magnitude and the height reductions ranging from 20% to 60% at an interval of 10%. Based on the experimental results in isothermal compression of Ti–6Al–4V alloy, the effect of processing parameters and grain size of primary α phase on the strain rate sensitivity Exponent m and the strain Hardening Exponent n is in depth analyzed. The strain rate sensitivity Exponent m at a strain of 0.7 and strain rate of 0.001 s −1 firstly tends to increase with the increasing of deformation temperature, and maximum m value is obtained at deformation temperature close to the beta-transus temperature, while at higher deformation temperature it drops to the smaller values. Moreover, the strain rate sensitivity Exponent m decreases with the increasing of strain rate at the deformation temperatures below 1253 K, but the m values become maximal at a strain rate of 0.01 s −1 and the deformation temperature above 1253 K. The strain rate affects the variation of strain rate sensitivity Exponent with strain. Those phenomena can be explained reasonably based on the microstructural evolution. On the other hand, the strain Hardening Exponent n depends strongly on the strain rate at the strains of 0.5 and 0.7. The strain affects significantly the strain Hardening Exponent n due to the variation of grain size of primary α phase with strain, and the competition between thermal softening and work Hardening.
Wenzhen Zhao - One of the best experts on this subject based on the ideXlab platform.
-
formula relating fracture strength and fracture ductility with strength coefficient and strain Hardening Exponent
Journal of Materials Engineering and Performance, 2006Co-Authors: Zhongping Zhang, Qiang Sun, Yanjian Qiao, Wenzhen ZhaoAbstract:To theoretically calculate the strength coefficient and the strain-Hardening Exponent with conventional mechanical property parameters, formulas relating them with fracture strength and fracture ductility are studied using test data for ten alloys. The applicability of the traditional formula relating these four material constants is discussed first, and then new formulas are proposed based on the premise that the traditional approach cannot be used. The main conclusions made herein are that only under certain conditions can be traditional formula be used to describe the relationship among fracture strength, fracture ductility, strength coefficient, and strain-Hardening Exponent; otherwise, a new formula must be used.
-
theoretical calculation of the strain Hardening Exponent and the strength coefficient of metallic materials
Journal of Materials Engineering and Performance, 2006Co-Authors: Zhongping Zhang, Wenzhen Zhao, Qiang SunAbstract:The purpose of the present article is to theoretically calculate the strain-Hardening Exponent and the strength coefficient of metallic materials. For this purpose, two equations are used. The first one correlates the strain-Hardening Exponent and the strength coefficient with the yield stress-strain behavior, while the other one correlates the fracture strength and the fracture ductility. From these two equations, the expressions of both the strain-Hardening Exponent and the strength coefficient are deduced. Theoretical results from the deduced expressions are then compared with test data. Through the comparison of equations and data, if adequate test data are lacking, the deduced expressions can be used to theoretically calculate the strain-Hardening Exponent and the strength coefficient for metallic materials. The characteristics of the theoretical approach are simple and easy to use. In addition, the theoretical results can be further applied to examine the correctness of the test data.