Mechanical Properties of Al-Cu Films with Various Heat Treatments

1997 ◽  
Vol 473 ◽  
Author(s):  
Young-Chang Joo ◽  
Peter Müllner ◽  
Shefford P. Baker ◽  
Eduard Arzt
Keyword(s):  
Precipitation Hardening ◽  
Heat Treatments ◽  
Temperature Cycling ◽  
Solid Solution Hardening ◽  
Solution Hardening ◽  
Cu Films ◽  
Cu Content ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Compressive Flow

ABSTRACTPrecipitation and solid solution hardening have been studied in Al-Cu thin films with Cu content ranging from 0 to 2 wt%. We have changed the precipitate and dislocation structures of films having different Cu concentrations by varying the heat treatments prior to mechanical testing. Pure Al films showed the same values of tensile and compressive yield stresses at a given temperature during stress-temperature cycling. Al-Cu alloy films, however, showed larger stresses in tension than in compression. The compressive flow stress during heating could be changed by a factor of five by the initial heat treatment, but the differences disappeared above 250°C. Upon cooling from 480°C, solution hardening as well as precipitation hardening was observed in the Al-Cu films. Solution hardening is independent of Cu concentration, but for precipitation hardening, both the magnitude and the temperature range in which the mechanism is effective are sensitive to the Cu concentration. The microstructure was observed using transmission electron microscopy. The mechanical behavior is consistent with interactions between dislocations and precipitates which arise due to constraints on the film by the substrate.

Effects of Zr and Sc additions on precipitation of α-Al(FeMn)Si dispersoids under various heat treatments in Al–Mg–Si AA6082 alloys

2021 ◽  
Vol 112 (9) ◽  
pp. 706-716
Author(s):  
Kun Liu ◽  
Emad Elgallad ◽  
Chen Li ◽  
X.-Grant. Chen
Keyword(s):  
Solid Solution ◽  
Precipitation Hardening ◽  
Base Alloy ◽  
Heat Treatments ◽  
Solid Solution Hardening ◽  
Number Density ◽  
Solution Hardening ◽  
Heat Treated ◽  
The Individual

Abstract The present work investigated the influence of Zr and Sc on the evolution of α-Al(FeMn)Si dispersoids (“α-dispersoids") in Al–Mg–Si alloys. Both the individual addition of Zr and the combined additions of Sc and Zr increased the size but decreased the number density of the α-dispersoids, indicating the reduction in the formation of α-dispersoids. However, the reduction levels were the most significant when heat-treated at 350 °C in the alloy with both Sc and Zr and at 400 °C in the alloy with only Zr, which were likely related to the different interactions between intermediate B’ precipitates and α-dispersoids with the addition of Zr and Sc. Although the α-dispersoids were suppressed in the Zr/Sc-containing alloys, their microhardness was generally higher than the base alloy, which can be attributed to the strengthening contribution induced by Zr and Sc either from their solid solution hardening or the precipitation hardening of Al3Zr/Al3(Sc, Zr) dispersoids.

Cu concentration dependence of the mechanical behaviour of Al-Cu alloys

1999 ◽  
Vol 564 ◽  
Author(s):  
J. P. Lokker ◽  
R. S. A. van Winden ◽  
A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Thin Films ◽  
Tensile Stress ◽  
Mechanical Behaviour ◽  
Precipitation Hardening ◽  
Solid Solution Hardening ◽  
Isothermal Hold ◽  
Solution Hardening ◽  
Stress Increase ◽  
Si Substrates ◽  
Cu Alloys

AbstractThis paper reports on the influence of the copper concentration on the mechanical behaviour during thermal cycling and during isothermal holds of Al-Cu thin films on Si substrates. The Cu concentration has been varied in the range between 0 to 1 at.%Upon heating, the films with the larger amount of Cu showed a clear maximum in compressive stress. Moreover, during cooling these samples show a tensile stress increase at the onset precipitation temperature. Further cooling below 200 °C leads to the characteristic tensile stress increase often observed for Al-Cu thin films. An isothermal hold during cooling at 250 °C leads to temporary strengthening of all Al-Cu. The extent of the strengthening is dependent on the Cu concentration and is clearly dependent on the duration of the isothermal hold. Upon further cooling the strengthening disappears and the stress develops according to the original stress temperature dependence. The observations are discussed in terms of solid solution hardening and precipitation hardening.

scholarly journals Solid Solution Hardening and Precipitation Hardening of α2-Ti3Al in Ti-Al-Nb Alloys

2017 ◽  
Vol 58 (10) ◽  
pp. 1404-1410 ◽  
Author(s):  
Kei Shimagami ◽  
Sae Matsunaga ◽  
Atsushi Yumoto ◽  
Tsutomu Ito ◽  
Yoko Yamabe-Mitarai
Keyword(s):  
Solid Solution ◽  
Precipitation Hardening ◽  
Solid Solution Hardening ◽  
Solution Hardening

Progress in Creep-Resistant Steels for High Efficiency Coal-Fired Power Plants

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Fujio Abe
Keyword(s):  
Solid Solution ◽  
Creep Strength ◽  
Power Plants ◽  
Precipitation Hardening ◽  
High Efficiency ◽  
Austenitic Steels ◽  
Solid Solution Hardening ◽  
Solution Hardening ◽  
Creep Resistant Steels ◽  
Grade 91

Recent progress in creep-resistant bainitic, martensitic, and austenitic steels for high efficiency coal-fired power plants is comprehensively reviewed with emphasis on long-term creep strength and microstructure stability at grain boundaries (GBs). The creep strength enhanced ferritic (CSEF) steels, such as Grade 91 (9Cr–1Mo–0.2V–0.05Nb), Grade 92 (9Cr–0.5Mo–1.8W–VNb), and Grade 122 (11Cr–0.4Mo–2W–1CuVNb), can offer the highest potential to meet the required flexibility for ultra-supercritical (USC) power plants operating at around 600 °C, because of their smaller thermal expansion and larger thermal conductivity than austenitic steels and Ni base alloys. Further improvement of creep strength of martensitic 9 to 12Cr steels has been achieved by substituting a part or all of Mo with W and also by the addition of Co, V, Nb, and boron. A martensitic 9Cr–3W–3Co–VNb steel strengthened by boron and MX nitrides, designated MARBN, exhibits not only much higher creep strength of base metal than Grade 91, Grade 92, and Grade 122 but also substantially no degradation in creep strength due to type IV fracture in welded joints at 650 °C. High-strength bainitic 2.25 to 3Cr steels have been developed by enhancing solid solution hardening due to W and precipitation hardening due to (V,Nb)C carbides in bainitic microstructure. The improvement of creep strength of austenitic steels has been achieved by solid solution hardening due to the addition of Mo, W, and nitrogen and by precipitation hardening due to the formation of fine MX (M = Ti, Nb, X = C, N), NbCrN, M23C6, Cu phase, and Fe2(Mo,W) Laves phase. The boundary and sub-boundary hardening are shown to be the most important strengthening mechanism in creep of creep-resistant steels and is enhanced by fine dispersions of precipitates along boundaries.

Ageing Behavior of Cu-Ag Alloys

2008 ◽  
Vol 47-50 ◽  
pp. 1051-1054 ◽  
Author(s):  
Hoon Cho ◽  
Byoung Soo Lee ◽  
Bok Hyun Kang ◽  
Ki Young Kim
Keyword(s):  
Solid Solution ◽  
Electrical Conductivity ◽  
Tensile Strength ◽  
Mechanical Strength ◽  
Solid Solution Hardening ◽  
Large Drop ◽  
Solution Hardening ◽  
Ageing Treatment ◽  
Cu Alloy ◽  
Annealed Copper

To develop Cu alloy with tensile strength of 800 MPa and electrical conductivity of 80 %IACS (International Annealed Copper Standard), the variation of mechanical strength and electrical conductivity in Cu-Ag alloy during fabrication processes including casting, solid solution and ageing treatment were investigated. Solid solution hardening leads to a large drop in electrical conductivity of Cu-Ag alloys due to super-saturation of Ag solute in Cu matrix. Ageing hardening gives rise to enhance both of the mechanical strength and the electrical conductivity. Therefore, it can be mentioned that the electrical conductivity of Cu-Ag alloys was affected dominantly by Ag solute in Cu matrix.

Influence of W in Solid Solution on the Creep Rate of Nickel

2018 ◽  
Author(s):  
Jing Zhang ◽  
Rolf Sandström
Keyword(s):  
Solid Solution ◽  
Creep Rate ◽  
Precipitation Hardening ◽  
Solid Solution Hardening ◽  
Solution Hardening ◽  
Solute Content ◽  
High Temperature Alloys ◽  
Cottrell Atmosphere ◽  
Vital Element ◽  
Wide Usage

Ni and Ni-W binary alloys are basis for nickel based superalloys. For most nickel based superalloys, strengthening mechanisms include both solid solution hardening and precipitation hardening. W is a vital element to create solid solution hardening and to improve the creep strength. In spite of its wide usage to strengthening of high temperature alloys, the mechanisms for solid solution hardening are not fully quantified. From the assumption that it is due to the attraction of solute atoms to dislocations and formation of Cottrell atmosphere to slow down the motion of dislocations, a fundamental model has been formulated previously. In the present paper, the model is expanded by taking the stacking fault energy and strain induced vacancies into account. Important parameters in the model are the variation of the lattice constant and the shear modulus with alloying content. Models for these variations have been formulated as a function of solute content. Another important parameter is the maximum interaction energy between the dislocations and the solutes. The model can satisfactorily predict both the large difference in creep rate between pure Ni and Ni-W alloys and the comparatively smaller differences between the three investigated Ni-2W, Ni-4W and Ni-6W alloys.

CRYSTALLIZATION BEHAVIOR OF AMORPHOUS TI-NI-CU ALLOY RIBBONS

2008 ◽  
Vol 01 (02) ◽  
pp. 145-149 ◽  
Author(s):  
JUNG MIN NAM ◽  
YONG HEE LEE ◽  
TAE HYUN NAM ◽  
YEON WOOK KIM ◽  
JUNG MOO LEE
Keyword(s):  
Melt Spinning ◽  
Crystallization Behavior ◽  
Glass Forming Ability ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Cu Content ◽  
Glass Forming ◽  
Cu Alloy ◽  
Transmission Electron

Amorphous Ti 50 Ni (50-x) Cu x (at.%) (x = 15, 20 and 25) alloy ribbons were prepared by melt spinning, and then their crystallization behavior was investigated by optical microscopy, transmission electron microscopy, X-ray diffraction and differential scanning calorimetry. Wavenumber (Qp) decreased from 29.40 nm-1 to 29.29 nm-1 and ΔT(T g - T x ) increased from 31 K to 36 K with increasing Cu content from 15 at.% to 25 at.%, suggesting that glass forming ability of Ti – Ni – Cu alloy ribbons increased with increasing Cu content. Activation energy for crystallization decreased from 211.5 kJ/mol to 136.4 kJ/mol with increasing Cu content from 15 at.% to 25 at.%, suggesting that a stability of Ti – Ni – Cu amorphous decreased with increasing Cu content.

Influence of Heat Treatments on Microstructures in an Fe-Co-V Alloy

1974 ◽  
Vol 32 ◽  
pp. 512-513
Author(s):  
S. Mahajan ◽  
M. R. Pinnel ◽  
J. E. Bennett
Keyword(s):  
Single Phase ◽  
Alloy Composition ◽  
Supersaturated Solid Solution ◽  
Cell Formation ◽  
Heat Treatments ◽  
Air Cooling ◽  
Iced Brine ◽  
Transmission Electron ◽  
The Matrix ◽  
Bcc Structure

The microstructural changes in an Fe-Co-V alloy (composition by wt.%: 2.97 V, 48.70 Co, 47.34 Fe and balance impurities, such as C, P and Ni) resulting from different heat treatments have been evaluated by optical metallography and transmission electron microscopy. Results indicate that, on air cooling or quenching into iced-brine from the high temperature single phase ϒ (fcc) field, vanadium can be retained in a supersaturated solid solution (α2) which has bcc structure. For the range of cooling rates employed, a portion of the material appears to undergo the γ-α2 transformation massively and the remainder martensitically. Figure 1 shows dislocation topology in a region that may have transformed martensitically. Dislocations are homogeneously distributed throughout the matrix, and there is no evidence for cell formation. The majority of the dislocations project along the projections of <111> vectors onto the (111) plane, implying that they are predominantly of screw character.

Deviations from Ideal Decagonal Symmetry in Electron Diffraction Patterns of the “Decagonal” Phase in the Al-Co-Cu Alloy System

1991 ◽  
Vol 49 ◽  
pp. 914-915
Author(s):  
Atul S. Ramani ◽  
Earle R. Ryba ◽  
Paul R. Howell
Keyword(s):  
Electron Microscope ◽  
Alloy System ◽  
Nominal Composition ◽  
Dimensional Lattice ◽  
3 Dimensional ◽  
Decagonal Phase ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Lattice Periodicity ◽  
Diffraction Patterns

The “decagonal” phase in the Al-Co-Cu system of nominal composition Al65CO15Cu20 first discovered by He et al. is especially suitable as a topic of investigation since it has been claimed that it is thermodynamically stable and is reported to be periodic in the dimension perpendicular to the plane of quasiperiodic 10-fold symmetry. It can thus be expected that it is an important link between fully periodic and fully quasiperiodic phases. In the present paper, we report important findings of our transmission electron microscope (TEM) study that concern deviations from ideal decagonal symmetry of selected area diffraction patterns (SADPs) obtained from several “decagonal” phase crystals and also observation of a lattice of main reflections on the 10-fold and 2-fold SADPs that implies complete 3-dimensional lattice periodicity and the fundamentally incommensurate nature of the “decagonal” phase. We also present diffraction evidence for a new transition phase that can be classified as being one-dimensionally quasiperiodic if the lattice of main reflections is ignored.

Sign in / Sign up

Export Citation Format

Share Document