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D S Sarma - One of the best experts on this subject based on the ideXlab platform.
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on the variation of lattice parameter of cu solid solution with Solute Content in cu ti alloys
Scripta Materialia, 1999Co-Authors: S. Nagarjuna, D S SarmaAbstract:The properties and structure of age hardenable Cu-Ti alloys have been studied extensively to assess their suitability as a substitute for the toxic and expensive Cu-Be alloys. The earlier studies reported a sharp increase in hardness and strength and marked decrease in electrical resistivity in solution treated Cu-Ti alloys at Ti Contents greater than 4.0 wt% and it was attributed to fine scale precipitation in the form of modulations in Cu-4.5Ti and Cu{sub 4}Ti, {beta}{sup 1} precipitate in Cu-5.4Ti alloys, formed during quenching itself. Further, such sharp changes were not observed in the peak aged condition due to uniform precipitation of Cu{sub 4}Ti, {beta}{sup 1} phase in all the four Cu-Ti alloys. However, the effect of Solute Content on the lattice parameter of {alpha}-Cu has not been investigated. The variation of lattice parameter of {alpha}-Cu with Ti Content in solution treated (ST) and ST + peak aged conditions is presented in this paper.
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on the variation of mechanical properties with Solute Content in cu ti alloys
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 1999Co-Authors: S. Nagarjuna, Karthikeyan Balasubramanian, M Srinivas, D S SarmaAbstract:Abstract The variation of mechanical properties and electrical conductivity of Cu–Ti alloys of four compositions, viz. Cu–1.5 wt%Ti, Cu–2.7 wt%Ti, Cu–4.5 wt%Ti, and Cu–5.4 wt%Ti, have been studied in solution treated (ST), solution treated+peak aged (ST+PA), and solution treated+cold worked+peak aged (ST+CW+PA) conditions. In the ST condition, Ti is found to be a potential solid solution strengthener of copper showing greater effect than other elements like Zn, Ni, Al, Si, Be, and Sn. Solid solution strengthening in Cu–Ti alloys is attributed to the interaction of titanium atoms with screw dislocations and the effective interaction is more due to modulus mismatch than size misfit. Further, a marked change in the linear variation of tensile strength and elongation with Ti Content is observed at about 4.0 wt%Ti beyond which, tensile strength increases sharply while elongation decreases further, which is attributed to fine scale precipitation formed during quenching of Cu–4.5 Ti and Cu–5.4 Ti alloys. On the other hand, hardness and tensile properties increase linearly up to 5.4 wt%Ti in the peak aged condition with or without prior cold work, due to uniform precipitation of Cu 4 Ti, β l phase in all the four alloys. The increase in yield and tensile strengths due to solid solution strengthening, cold work, and precipitation have been determined quantitatively in ST+CW+PA alloys. While electrical conductivity is less, the mechanical properties of Cu–Ti alloys are comparable with those of commercial Cu–Be alloys.
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On the variation of mechanical properties with Solute Content in Cu-Ti alloys
Materials Science and Engineering A, 1999Co-Authors: S. Nagarjuna, Karthikeyan Balasubramanian, M Srinivas, D S SarmaAbstract:The variation of mechanical properties and electrical conductivity of Cu-Ti alloys of four compositions, viz. Cu-1.5 wt%Ti, Cu-2.7 wt%Ti, Cu-4.5 wt%Ti, and Cu-5.4 wt%Ti, have been studied in solution treated (ST), solution treated + peak aged (ST + PA), and solution treated + cold worked + peak aged (ST + CW + PA) conditions. In the ST condition, Ti is found to be a potential solid solution strengthener of copper showing greater effect than other elements like Zn, Ni, Al, Si, Be, and Sn. Solid solution strengthening in Cu-Ti alloys is attributed to the interaction of titanium atoms with screw dislocations and the effective interaction is more due to modulus mismatch than size misfit. Further, a marked change in the linear variation of tensile strength and elongation with Ti Content is observed at about 4.0 wt%Ti beyond which, tensile strength increases sharply while elongation decreases further, which is attributed to fine scale precipitation formed during quenching of Cu-4.5 Ti and Cu-5.4 Ti alloys. On the other hand, hardness and tensile properties increase linearly up to 5.4 wt%Ti in the peak aged condition with or without prior cold work, due to uniform precipitation of Cu4Ti, β1phase in all the four alloys. The increase in yield and tensile strengths due to solid solution strengthening, cold work, and precipitation have been determined quantitatively in ST + CW + PA alloys. While electrical conductivity is less, the mechanical properties of Cu-Ti alloys are comparable with those of commercial Cu-Be alloys. © 1999 Elsevier Science S.A. All rights reserved.
S. Nagarjuna - One of the best experts on this subject based on the ideXlab platform.
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on the variation of lattice parameter of cu solid solution with Solute Content in cu ti alloys
Scripta Materialia, 1999Co-Authors: S. Nagarjuna, D S SarmaAbstract:The properties and structure of age hardenable Cu-Ti alloys have been studied extensively to assess their suitability as a substitute for the toxic and expensive Cu-Be alloys. The earlier studies reported a sharp increase in hardness and strength and marked decrease in electrical resistivity in solution treated Cu-Ti alloys at Ti Contents greater than 4.0 wt% and it was attributed to fine scale precipitation in the form of modulations in Cu-4.5Ti and Cu{sub 4}Ti, {beta}{sup 1} precipitate in Cu-5.4Ti alloys, formed during quenching itself. Further, such sharp changes were not observed in the peak aged condition due to uniform precipitation of Cu{sub 4}Ti, {beta}{sup 1} phase in all the four Cu-Ti alloys. However, the effect of Solute Content on the lattice parameter of {alpha}-Cu has not been investigated. The variation of lattice parameter of {alpha}-Cu with Ti Content in solution treated (ST) and ST + peak aged conditions is presented in this paper.
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on the variation of mechanical properties with Solute Content in cu ti alloys
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 1999Co-Authors: S. Nagarjuna, Karthikeyan Balasubramanian, M Srinivas, D S SarmaAbstract:Abstract The variation of mechanical properties and electrical conductivity of Cu–Ti alloys of four compositions, viz. Cu–1.5 wt%Ti, Cu–2.7 wt%Ti, Cu–4.5 wt%Ti, and Cu–5.4 wt%Ti, have been studied in solution treated (ST), solution treated+peak aged (ST+PA), and solution treated+cold worked+peak aged (ST+CW+PA) conditions. In the ST condition, Ti is found to be a potential solid solution strengthener of copper showing greater effect than other elements like Zn, Ni, Al, Si, Be, and Sn. Solid solution strengthening in Cu–Ti alloys is attributed to the interaction of titanium atoms with screw dislocations and the effective interaction is more due to modulus mismatch than size misfit. Further, a marked change in the linear variation of tensile strength and elongation with Ti Content is observed at about 4.0 wt%Ti beyond which, tensile strength increases sharply while elongation decreases further, which is attributed to fine scale precipitation formed during quenching of Cu–4.5 Ti and Cu–5.4 Ti alloys. On the other hand, hardness and tensile properties increase linearly up to 5.4 wt%Ti in the peak aged condition with or without prior cold work, due to uniform precipitation of Cu 4 Ti, β l phase in all the four alloys. The increase in yield and tensile strengths due to solid solution strengthening, cold work, and precipitation have been determined quantitatively in ST+CW+PA alloys. While electrical conductivity is less, the mechanical properties of Cu–Ti alloys are comparable with those of commercial Cu–Be alloys.
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On the variation of mechanical properties with Solute Content in Cu-Ti alloys
Materials Science and Engineering A, 1999Co-Authors: S. Nagarjuna, Karthikeyan Balasubramanian, M Srinivas, D S SarmaAbstract:The variation of mechanical properties and electrical conductivity of Cu-Ti alloys of four compositions, viz. Cu-1.5 wt%Ti, Cu-2.7 wt%Ti, Cu-4.5 wt%Ti, and Cu-5.4 wt%Ti, have been studied in solution treated (ST), solution treated + peak aged (ST + PA), and solution treated + cold worked + peak aged (ST + CW + PA) conditions. In the ST condition, Ti is found to be a potential solid solution strengthener of copper showing greater effect than other elements like Zn, Ni, Al, Si, Be, and Sn. Solid solution strengthening in Cu-Ti alloys is attributed to the interaction of titanium atoms with screw dislocations and the effective interaction is more due to modulus mismatch than size misfit. Further, a marked change in the linear variation of tensile strength and elongation with Ti Content is observed at about 4.0 wt%Ti beyond which, tensile strength increases sharply while elongation decreases further, which is attributed to fine scale precipitation formed during quenching of Cu-4.5 Ti and Cu-5.4 Ti alloys. On the other hand, hardness and tensile properties increase linearly up to 5.4 wt%Ti in the peak aged condition with or without prior cold work, due to uniform precipitation of Cu4Ti, β1phase in all the four alloys. The increase in yield and tensile strengths due to solid solution strengthening, cold work, and precipitation have been determined quantitatively in ST + CW + PA alloys. While electrical conductivity is less, the mechanical properties of Cu-Ti alloys are comparable with those of commercial Cu-Be alloys. © 1999 Elsevier Science S.A. All rights reserved.
Amauri Garcia - One of the best experts on this subject based on the ideXlab platform.
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The correlation between dendritic microstructure and mechanical properties of directionally solidified hypoeutectic Al-Ni alloys
Metals and Materials International, 2010Co-Authors: Manuel V. Canté, Jose E Spinelli, Noé Cheung, Amauri GarciaAbstract:Al-Ni hypoeutectic alloys were directionally solidified under upward transient heat flow conditions. The aim of the present study is to set up correlations between the as-cast microstructure and the resulting mechanical properties of these alloys. The dependence of primary and secondary dendrite arm spacing on the alloy Solute Content and on solidification thermal parameters is also analyzed. The results include transient metal/mold heat transfer coefficient, tip growth rate, cooling rate, dendrite arm spacing, ultimate tensile strength, yield tensile strength and elongation. Expressions relating dendrite spacing to solidification thermal parameters and mechanical properties to the scale of the dendritic microstructure have been determined. It was found that the ultimate tensile strength and the yield tensile strength increase with increasing alloy Solute Content and with decreasing primary and secondary dendrite arm spacing. In contrast, the elongation was found to be independent of both alloy composition and dendritic arrangement.
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influences of Solute Content melt superheat and growth direction on the transient metal mold interfacial heat transfer coefficient during solidification of sn pb alloys
Materials Chemistry and Physics, 2008Co-Authors: Ivaldo L Ferreira, Jose E Spinelli, Britta Nestler, Amauri GarciaAbstract:Abstract Several factors such as alloy composition, melt superheat, mold material, roughness of inner mold surface, mold coating layer, etc., can affect the transient metal/mold heat transfer coefficient, hi. An accurate casting solidification model should be able to unequivocally consider these effects on hi determination. After this previous knowledge on interfacial heat transfer, such models might be used to control the process based on thermal and operational parameters and to predict microstructure which affects casting final properties. In the present work, three different directional solidification systems were designed in such a way that thermal data could be monitored no matter what configuration was tested with respect to the gravity vector: vertical upward and downward or horizontal. Experiments were carried-out with Sn–Pb hypoeutectic alloys (5 wt.% Pb, 10 wt.% Pb, 15 wt.% Pb and 30 wt.% Pb) for investigating the influence of Solute Content, growth direction and melt superheat on hi values. The experimentally obtained temperatures were used by a numerical technique in order to determine time-varying hi values. It was found that hi rises with decreasing lead Content of the alloy, and that hi profiles can be affected by the initial melt temperature distribution.
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Influences of Solute Content, melt superheat and growth direction on the transient metal/mold interfacial heat transfer coefficient during solidification of Sn–Pb alloys
Materials Chemistry and Physics, 2008Co-Authors: Ivaldo L Ferreira, Jose E Spinelli, Britta Nestler, Amauri GarciaAbstract:Abstract Several factors such as alloy composition, melt superheat, mold material, roughness of inner mold surface, mold coating layer, etc., can affect the transient metal/mold heat transfer coefficient, hi. An accurate casting solidification model should be able to unequivocally consider these effects on hi determination. After this previous knowledge on interfacial heat transfer, such models might be used to control the process based on thermal and operational parameters and to predict microstructure which affects casting final properties. In the present work, three different directional solidification systems were designed in such a way that thermal data could be monitored no matter what configuration was tested with respect to the gravity vector: vertical upward and downward or horizontal. Experiments were carried-out with Sn–Pb hypoeutectic alloys (5 wt.% Pb, 10 wt.% Pb, 15 wt.% Pb and 30 wt.% Pb) for investigating the influence of Solute Content, growth direction and melt superheat on hi values. The experimentally obtained temperatures were used by a numerical technique in order to determine time-varying hi values. It was found that hi rises with decreasing lead Content of the alloy, and that hi profiles can be affected by the initial melt temperature distribution.
Benjamin Milkereit - One of the best experts on this subject based on the ideXlab platform.
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quench induced precipitates in al si alloys calorimetric determination of Solute Content and characterisation of microstructure
Thermochimica Acta, 2015Co-Authors: Philipp Schumacher, Stefan Pogatscher, M J Starink, Christoph Schick, Volker Mohles, Benjamin MilkereitAbstract:The present study introduces an experimental approach to investigate mechanical properties of well-defined non-equilibrium states of Al–Si alloys during cooling from solution annealing. The precipitation behaviour of binary Al–Si alloys during the cooling process has been investigated in a wide cooling rate range (2–0.0001 K/s) with differential scanning calorimetry (DSC). To access the low cooling rate range close to equilibrium an indirect DSC measurement method is introduced. Based on the enthalpy change measured by DSC a physically-based model for the calculation of remaining Solute Si amount as function of temperature and cooling rate is presented. Microstructural analyses via light optical microscopy, scanning electron microscopy, atom probe tomography and X-ray diffraction have been performed to evaluate the introduced model and for information on cooling rate dependent precipitate formation. It was found that quench-induced particles of different morphology are formed during cooling. Thermomechanical analyses on clearly distinct undercooled Al–Si states show that flow stress during cooling is dependent on temperature as well as cooling rate. The mechanical behaviour is therefore influenced by Solute Si Content and quench-induced precipitates.
C H Caceres - One of the best experts on this subject based on the ideXlab platform.
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Alloy Composition and Dendrite Arm Spacing in Al-Si-Cu-Mg-Fe Alloys
Metallurgical and Materials Transactions A, 2013Co-Authors: Tharmalingam Sivarupan, C H Caceres, John A. TaylorAbstract:Six Al-Si-Cu-Mg-(Fe/Mn) alloys with two levels of each of Cu, Si, and Fe/Mn were cast in the form of quasi-directionally solidified plates. The secondary dendrite arm spacing (SDAS) was measured as a function of the distance from the chill end for each composition and related to the local cooling rate as determined by thermocouples embedded in one of the cast plates. For a given cooling rate, Si has a strong, consistently refining effect on the SDAS per unit of Solute Content. Cu showed its strongest refining effect at low-Si and high-Fe Contents. It is argued that the scale of the SDAS is determined by a combination of five main factors: constitutional undercooling; the fraction of Al-Si eutectic; and the amount, morphology, and distribution of the various intermetallic phases. The first two factors affect the early stages of the dendrite structure and SDAS formation, whereas the ones involving intermetallics affect the dendrite-coarsening mechanisms in the post-eutectic stage. The latter ones are more sensitive to cooling rate than the ones involving Solute in solution. The scales of both, SDAS and intermetallics, can be predetermined to a measurable extent through the Solute Content to best suit particular casting conditions.
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Solute Content and the grain microstructure of high pressure diecast magnesium aluminium alloys
Advanced Engineering Materials, 2009Co-Authors: A V Nagasekhar, Mark Alan Easton, C H CaceresAbstract:The grain microstructure is strongly bimodal due to the mixture of large dendritic grains that solidify in the shot sleeve and are subsequently injected into the die cavity, and the small grains that nucleate inside the cavity and grow to a size dictated by the Solute Content and the solidification rate. The large grains form only in concentrated alloys; their size is also partially controlled by the growth restriction factor.
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Solute Content and the Grain Microstructure of High Pressure Diecast Magnesium–Aluminium Alloys
Advanced Engineering Materials, 2009Co-Authors: A V Nagasekhar, Mark Easton, C H CaceresAbstract:The grain microstructure is strongly bimodal due to the mixture of large dendritic grains that solidify in the shot sleeve and are subsequently injected into the die cavity, and the small grains that nucleate inside the cavity and grow to a size dictated by the Solute Content and the solidification rate. The large grains form only in concentrated alloys; their size is also partially controlled by the growth restriction factor.
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Reversible plastic strain during cyclic loading–unloading of Mg and Mg–Zn alloys
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2007Co-Authors: Gemma. Mann, C H Caceres, Taro Sumitomo, J.r. GriffithsAbstract:Abstract Large hysteresis loops are observed during cyclic loading–unloading of Mg and Mg–Zn alloys. This is true for both tension and compression cycling, for grain sizes between 25 and 670 μm, and for Zn Contents between 0 and 6 mass%. The loops are ascribed to anelasticity resulting from elastic { 1 0 1 ¯ 2 } twinning. The anelastic strain increases with the strain and reaches a maximum at strains between about 1 and 2%. For a given total strain, the amount of anelastic strain increases with decreasing grain size, and decreases with increasing Zn Content. The maximum observed anelastic strain is about 0.3% for pure Mg, decreasing with the Solute Content to about 0.2% for Mg–6 mass% Zn. The phenomenon is discussed in terms of the effect of Solute Content and grain size on the formation and stability of twins.