On the hot working characteristics of 6061Al-SiC and 6061-Al2O3 particulate reinforced metal matrix composites
TL;DR: In this paper, a simple instability condition for assessing the extent of plastic deformation in a workpiece prior to the formation of defects, is derived based on the Ziegler's continuum principles.
About: This article is published in Composites Science and Technology.The article was published on 2003-01-01. It has received 85 citations till now. The article focuses on the topics: Flow stress & Hot working.
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TL;DR: In this article, the fabrication and mechanical investigation of aluminium alloy, alumina (Al2O3) and boron carbide metal matrix composites is discussed, where the fabrication is done by stir casting which involves mixing the required quantities of additives into stirred molten aluminium.
244 citations
Cites background from "On the hot working characteristics ..."
...[14], worked on the hot working characteristics of 6061Al–SiC and 6061–Al2O3 particulate reinforcedmetal matrix composites for the development of processing maps....
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01 Jan 2014
TL;DR: In this article, the effect of different reinforcement on AMCs on the mechanical properties like tensile strength, strain, hardness, wear and fatigue is discussed in detail, and major applications of different AMCs are also highlighted in this work.
Abstract: Aluminium matrix composites (AMCs) are potential materials for various applications due to their good physical and mechanical properties. The addition of reinforcements into the metallic matrix improves the stiffness, specific strength, wear, creep and fatigue properties com- pared to the conventional engineering materials. This paper presents the overview of the effect of addition on different reinforcements in aluminium alloy highlighting their merits and demerits. Major issues like agglomerating phenomenon, fiber-matrix bonding and the problems related to distribution of particles are discussed in this paper. Effect of different reinforcement on AMCs on the mechanical properties like tensile strength, strain, hardness, wear and fatigue is also dis- cussed in detail. Major applications of different AMCs are also highlighted in this work.
136 citations
TL;DR: In this paper, the hot deformation behavior of Stir cast 7075 alloy was studied using processing map technique and the map has been interpreted in terms of the microstructural processes occurring in situ with deformation, based on the values of a dimensionless parameter η which is an efficiency index of energy dissipation through micro-structural process.
114 citations
15 Nov 2010-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
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
TL;DR: In this paper, the authors studied the hot deformation behavior of in situ 5-wt.% nano ZrB 2 /2024Al composite at deformation temperatures of 350-450°C and strain rates of 0.001-10−s −1.
58 citations
References
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01 Oct 1982
TL;DR: Deformation-mechanism maps: the plasticity and creep of metals and ceramics as discussed by the authors, Deformation-Mechanism Maps of metal deformation: the deformation and the creep of metal and ceramic.
Abstract: Deformation-mechanism maps: the plasticity and creep of metals and ceramics , Deformation-mechanism maps: the plasticity and creep of metals and ceramics , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی
2,342 citations
TL;DR: It is shown that nonequilibrium may become a source of order and that irreversible processes may lead to a new type of dynamic states of matter called "dissipative structures" and the thermodynamic theory of such structures is outlined.
Abstract: Fundamental conceptual problems that arise from the macroscopic and microscopic aspects of the second law of thermodynamics are considered. It is shown that nonequilibrium may become a source of order and that irreversible processes may lead to a new type of dynamic states of matter called "dissipative structures." The thermodynamic theory of such structures is outlined. A microscopic definition of irreversible processes is given, and a transformation theory is developed that allows one to introduce nonunitary equations of motion that explicitly display irreversibility and approach to thermodynamic equilibrium. The work of the group at the University of Brussels in these fields is briefly reviewed. In this new development of theoretical chemistry and physics, it is likely that thermodynamic concepts will play an ever-increasing role.
864 citations
31 May 2000-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a processing map has been developed on the basis of flow stress data as a function of temperature, strain rate and strain, which is used for obtaining processing windows and achieving microstructural control during hot working.
Abstract: The hot deformation behavior of Ti–6Al–4V with an equiaxed α–β preform microstructure is modeled in the temperature range 750–1100°C and strain rate range 0.0003–100 s−1, for obtaining processing windows and achieving microstructural control during hot working. For this purpose, a processing map has been developed on the basis of flow stress data as a function of temperature, strain rate and strain. The map exhibited two domains: (i) the domain in the α–β phase field is identified to represent fine-grained superplasticity and the peak efficiency of power dissipation occurred at about 825°C/0.0003 s−1. At this temperature, the hot ductility exhibited a sharp peak indicating that the superplasticity process is very sensitive to temperature. The α grain size increased exponentially with increase in temperature in this domain and the variation is similar to the increase in the β volume fraction in this alloy. At the temperature of peak ductility, the volume fraction of β is about 20%, suggesting that sliding of α–α interfaces is primarily responsible for superplasticity while the β phase present at the grain boundary triple junctions restricts grain growth. The apparent activation energy estimated in the α–β superplasticity domain is about 330 kJ mol−1, which is much higher than that for self diffusion in α-titanium. (ii) In the β phase field, the alloy exhibits dynamic recrystallization and the variation of grain size with temperature and strain rate could be correlated with the Zener–Hollomon parameter. The apparent activation energy in this domain is estimated to be 210 kJ mol−1, which is close to that for self diffusion in β. At temperatures around the transus, a ductility peak with unusually high ductility has been observed, which has been attributed to the occurrence of transient superplasticity of β in view of its fine grain size. The material exhibited flow instabilities at strain rates higher than about 1 s−1 and these are manifested as adiabatic shear bands in the α–β regime.
383 citations
TL;DR: In this article, a fracture initiation map is developed which should be useful in fast forming operations at strain rates greater than about 10-3 s-1 at elevated temperatures, and two types of cavitation mechanisms, one pertaining to cavity formation at second phase particles, as in ductile fracture, and the other pertaining to wedge type microcracking at grain boundaries, are considered.
Abstract: A fracture initiation map is developed which should be useful in fast forming operations at strain rates greater than about 10-3 s-1 at elevated temperatures. Two types of cavitation mechanisms, one pertaining to cavity formation at second phase particles, as in ductile fracture, and the other pertaining to wedge type microcracking at grain boundaries, are considered. In addition, dynamic recrystallization and adiabatic heating effects are considered. When these concepts are applied to aluminum, it is shown that there may be an intermediate region in the strain rate and temperature field in which neither of these mechanisms should operate and within which the material would, therefore, be safe from fracture.
313 citations