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Journal ArticleDOI

On the hot working characteristics of 2014 Al-20vol% Al2O3 metal matrix composite

TL;DR: In this article, a simple instability condition based on the Ziegler's continuum principles is extended for delineating the regions of unstable metal flow during hot deformation of 2014 Al-20vol% Al2O3 metal matrix composite.
About: This article is published in Journal of Materials Processing Technology.The article was published on 2005-08-01. It has received 49 citations till now. The article focuses on the topics: Metal matrix composite & Hot working.
Citations
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Journal ArticleDOI
TL;DR: In this paper, the authors studied the hot formability of a near-β titanium alloy near the β transus temperature to determine the mechanisms of deformation, where the achieved flow data were used to calculate the efficiency of power dissipation, the strain rate sensitivity, and instability parameters derived from different models.
Abstract: The hot formability of a near-β titanium alloy is studied near the β transus temperature to determine the mechanisms of deformation. Compression tests of Ti-5Al-5Mo-5V-3Cr-1Zr are carried out using a Gleeble®1500 device between 1036 K and 1116 K (763 °C and 843 °C) and strain rates between 0.001 and 10 s−1. The achieved flow data are used to calculate the efficiency of power dissipation, the strain rate sensitivity, and instability parameters derived from different models. Constitutive equations are built using the stress values at the strain of 0.4. Light optical microscopy and EBSD measurements are used to correlate the parameters that describe formability with the microstructure. It is found that hot deformation is achieved by dynamic recovery in the β phase by subgrain formation. Geometric dynamic recrystallization along the β grain boundaries takes place at large deformations, high temperatures, and low strain rates. On the other hand, for high strain rates, continuous dynamic recrystallization by lattice rotation already starts at a local strain of 1. Different phenomenological models are used to predict the flow instabilities, where the flow-softening parameter α i provides the best correlation with microstructure as well as the physical understanding. The instabilities observed in this alloy are strongly related to flow localization by adiabatic heat.

91 citations

Journal ArticleDOI
Gang Meng1, Bolong Li1, Hongmei Li1, Hui Huang1, Zuoren Nie1 
TL;DR: In this paper, the hot deformation behavior of an Al-5.7-wt.%Mg alloy with erbium has been investigated and the standard kinetic analysis has been applied to evaluate the rate controlling mechanisms.
Abstract: The hot deformation behavior of an Al–5.7 wt.%Mg alloy with erbium has been investigated. Compression tests are performed in the temperature range of 300–500 °C and in the strain rate ranging from 0.001 s−1 to 50 s−1 up to a true strain of 0.7. The processing maps are developed at different strains and the standard kinetic analysis has been applied to evaluate the rate controlling mechanisms. The processing maps have exhibited two domains of 350–450 °C at 0.001–0.03 s−1 and 450–500 °C at 0.01–1 s−1, representing dynamic recovery of Al–5.7 wt.%Mg with erbium. The apparent activation energies estimated in these two domains are 180 kJ/mol and 163 kJ/mol respectively, which suggests that cross-slip of dislocation and lattice self-diffusion are the deformation mechanisms. At strain rates higher than 10 s−1, the flow curves demonstrate flow softening behavior, and the flow instability regions reveal mixed microstructure of local deformation and dynamic recrystallization.

69 citations

Journal ArticleDOI
J.C. Shao1, B.L. Xiao1, Quanchao Wang1, Z.Y. Ma1, Liu Yuwan1, Ke Yang1 
TL;DR: In this article, the authors investigated the constitutive flow behavior and hot workability of powder metallurgy processed 20 vol.%SiC(P)/2024Al composite using hot compression tests.
Abstract: Constitutive flow behavior and hot workability of the powder metallurgy processed 20 vol.%SiC(P)/2024Al composite were investigated using hot compression tests. The modified Arrhenius-type constitutive equations were presented with the values of material constants in consideration as a function of strain. Dynamic material model (DMM) and modified DMM were used to construct the power dissipation efficiency maps, and Ziegler's instability criterion and Gegel's stability criterion were used to build instability maps. The presence of finer SiC(P) and more boundaries resulting from smaller 2024Al powders shifted the dynamic recrystallization domain of the 2024Al matrix to higher strain rate and lower temperature ranges and decreased the peak value of power dissipation efficiency. Large instable regions were found in the form of flow localization and cavitations located at the matrix/SiC(P) interfaces and within the SiC(P) clusters. By comparison, the Gegel's stability criterion was more sensitive to the instability zones than the Ziegler's instability criterion for this material. (c) 2010 Elsevier B.V. All rights reserved.

69 citations

Journal ArticleDOI
TL;DR: In this paper, the Zener-Hollomon parameter (Z ) in the domain of strain rates and temperatures has been investigated in hot compression tests performed on AISI1010 steel in the temperature range of 750°C-1050°C and strain rates range of 0.01-20s −1.

59 citations

Journal ArticleDOI
TL;DR: In this article, the deformation behavior of homogenized and forged AA2195 alloy was studied by hot isothermal compression in a thermo-mechanical simulator, and the contour maps of efficiency of power dissipation and instability maps have been generated within the temperature range of 250-450°C and strain rate range of 10−3-102 s−1.

57 citations

References
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Journal ArticleDOI
TL;DR: Bulk metal working processes are carried out at elevated temperatures where the occurrence of simultaneous softening processes would enable the imposition of large strains in a single step or multi-step process.
Abstract: Bulk metal working processes are carried out at elevated temperatures where the occurrence of simultaneous softening processes would enable the imposition of large strains in a single step or multi...

622 citations

Journal ArticleDOI
01 Sep 1981-JOM
TL;DR: In this article, a class of composites fabricated from inexpensive constituents, silicon carbide made from rice hulls and aluminum, which can be processed by conventional metal working techniques, is described.
Abstract: This paper describes a class of composites fabricated from inexpensive constituents, silicon carbide made from rice hulls and aluminum, which can be processed by conventional metal working techniques. Aluminum/silicon carbide composites can be extruded, rolled, forged, and pressed into engineering shapes. The mechanical properties of these composites as a function of silicon carbide loading fraction and aluminum matrix in a variety of shapes are presented.

141 citations

Journal ArticleDOI
TL;DR: In this paper, a hot working of Al alloy 2014-20vol.% Al2O3 particulate-reinforced cast-plus-extruded composite material has been generated covering the temperature range 300-500 degrees C and the strain rate range 0.001-10 s−1.
Abstract: The processing map for hot working of Al alloy 2014-20vol.%Al2O3 particulate-reinforced cast-plus-extruded composite material has been generated covering the temperature range 300-500 degrees C and the strain rate range 0.001-10 s(-1) based on the dynamic materials model. The efficiency eta of power dissipation given by 2m/(m + 1), where m is the strain rate sensitivity, is plotted as a function of temperature and strain rate to obtain a processing map. A domain of superplasticity has been identified, with a peak efficiency of 62% occurring at 500 degrees C and 0.001 s(-1). The characteristics of this domain have been studied with the help of microstructural evaluation and hot-ductility measurements. Microstructural instability is predicted at higher strain rates above (ls(-1)) and lower temperatures (less than 350 degrees C).

16 citations