Kinetic and Strength Calculation of Age-Hardening Phases in Heat-Resistant Aluminum Alloys with Silver

2020 ◽  
Vol 993 ◽  
pp. 1051-1056
Author(s):  
Jin San Wang
Keyword(s):  
Alloy System ◽  
S Phase ◽  
Strength Calculation ◽  
Age Hardening ◽  
Strengthening Effect ◽  
Heat Resistant ◽  
Ω Phase ◽  
Al2cu Phase ◽  
Equilibrium Phases ◽  
Strengthening Phases

In order to study the microstructures of heat-resistant aluminium alloys with silver in process of aging, kinetic and strength calculation were used to study the equilibrium and metastable phases of Al-4Cu-0.3Mg-0.4Ag alloy system. The main equilibrium phases were Liquid phase, α-Al matrix phase, Al2Cu phase, S phase (Al2CuMg) and AgMg phase, while metastable strengthening phases were Ω phase and θ’ phase. In addition, the kinetic parameters and aging strength of_Ω phase and θ’ phase that precipitated during aging were calculated. The calculated results shows that Ω phase has higher heat-resistant strengthening effect than θ’ phase.

Crystal Chemistry of Metastable Alloy Phases

1982 ◽  
Vol 19 ◽  
Author(s):  
B. C. Glessen
Keyword(s):  
Free Energy ◽  
Crystal Chemistry ◽  
Additional Data ◽  
Alloy System ◽  
Metastable Phases ◽  
Intermediate Phases ◽  
Free Energy Of Formation ◽  
Equilibrium Phases ◽  
Metastable Alloy ◽  
Energy Of Formation

Knowledge of the metastable crystalline alloy phases that can be prepared from the liquid or vapor by non-equilibrium methods is useful because the descriptive crystal chemistry of an alloy system should include metastable phases stable with respect to the components but unstable respective to other intermediate phases [1]. Alloy phases within a certain range of positive free energy of formation are also of interest, especially for systems without equilibrium phases. Accordingly, there have been some systematic “hunts” for metastable alloy phases (MAP's) that can be prepared by rapid liquid quenching, reviewed in Refs. 2–7. The principal results of these studies on disordered (element-like) and ordered MAP's and some additional data are presented here.

The Precession Technique in Electron Diffraction and Its Application to Structure Determination of Nano-Size Precipitates in Alloys

2004 ◽  
Vol 10 (1) ◽  
pp. 16-20 ◽  
Author(s):  
J. Gjønnes ◽  
V. Hansen ◽  
A. Kverneland
Keyword(s):  
Electron Diffraction ◽  
Alloy System ◽  
Age Hardening ◽  
Structure Model ◽  
Double Scattering ◽  
System A ◽  
Selected Area Electron Diffraction ◽  
Nano Size ◽  
High Resolution Microscopy

Crystal structure of nano-scale precipitates in age-hardening aluminum alloys is a challenge to crystallography. The utility of selected area electron diffraction intensities from embedded precipitates is limited by double scattering via matrix reflections. This effect can be signally reduced by the precession technique, which we have used to collect extensive intensity data from the semicoherent, metastable η′-precipitate in the Al-Zn-Mg alloy system. A structure model in the space group P-62c is proposed from high-resolution microscopy and electron diffraction intensities. The advantages of using the precession technique for quantitative electron diffraction is discussed.

Precipitation Hardening in Al-Cu-Mg Alloys: Analysis of Precipitates, Modelling of Kinetics, Strength Predictions

2006 ◽  
Vol 519-521 ◽  
pp. 251-258 ◽  
Author(s):  
Marco J. Starink ◽  
J.L. Yan
Keyword(s):  
Precipitation Hardening ◽  
Rapid Heating ◽  
Solution Treatment ◽  
Treatment Temperature ◽  
S Phase ◽  
Age Hardening ◽  
Solution Treatment Temperature ◽  
Hardening Mechanism ◽  
Mechanism Model ◽  
Constitutive Components

In Al-Cu-Mg with compositions in the α+S phase field, precipitation hardening is a twostage process. Experimental evidence shows that the main precipitation sequence in alloys with Cu contents in excess of 1wt% is involves Cu-Mg co-clusters, GPBII/S'' and S. The first stage of the age hardening is due to the formation of Cu-Mg co-clusters, and the hardening can be modelled well by a modulus hardening mechanism. The appearance of the orthorhombic GPBII/S'' does not influence the hardness. The second stage of the hardening is due to the precipitation of S phase, which strengthens the alloy predominantly through the Orowan looping mechanism. These findings are incorporated into a multi-phase, multi mechanism model for yield strength of Al-Cu-Mg based alloys. The model is applied to a range of alloys with Cu:Mg ratios between 0.1 and 1 and to heat treatments ranging from room temperature ageing and artificial isothermal ageing to rapid heating to the solution treatment temperature. The predictive capabilities of this model are reviewed and its constitutive components are compared and contrasted with a range of other methods, such as the Kampmann-Wagner and JMAK models for precipitation as well as the LSW model for coarsening.

Mechanical Behaviors of Ti-29Nb-13Ta-4.6Zr-XO for Biomedical Applications Subjected to Cold Working and Various Heat Treatments

2007 ◽  
Vol 561-565 ◽  
pp. 1471-1476
Author(s):  
Mitsuo Niinomi ◽  
Toshikazu Akahori ◽  
Masaaki Nakai ◽  
Hiroshi Ishikawa ◽  
Michiharu Ogawa
Keyword(s):  
Elastic Modulus ◽  
Oxygen Content ◽  
Biomedical Applications ◽  
Cold Working ◽  
Early Stage ◽  
Age Hardening ◽  
Mechanical Behaviors ◽  
Ω Phase ◽  
Α Phase ◽  
Effect Of Oxygen

The effect of oxygen content on aging behavior and invar characteristics of Ti-29Nb-13Ta-4.6Zr (TNTZ) were investigated. The age hardening of TNTZ aged at 573 K and 723 K is enhanced with the oxygen content. The ω phase precipitates and grows from early stage of aging in TNTZ regardless of the oxygen content when aged at 573 K. The lath-like shape α phase precipitated in TNTZ aged at 723 K increases in size with the oxygen content. The elastic modulus increases with the oxygen content and aging. The ω phase increase the elastic modulus to a greater extent than the increase due to the α phase. The tensile strength increases with the oxygen content and aging, while the elongation decreases. TNTZ with oxygen content of 0.1 mass% exhibits invar-like characteristics through severe cold working. A higher oxygen content suppresses the invar-like characteristics of TNTZ.

Phase Equilibria in the Sn-Rich Corner of the Sn–Cu–Ni Ternary Alloy System at 240 °C

2005 ◽  
Vol 20 (11) ◽  
pp. 3118-3124 ◽  
Author(s):  
Chia-Ying Li ◽  
Jenq-Gong Duh
Keyword(s):  
Flip Chip ◽  
Alloy System ◽  
Phase Region ◽  
Interfacial Reactions ◽  
X Ray Diffraction ◽  
Ternary Region ◽  
Chip Technology ◽  
Backscattered Electron ◽  
Equilibrium Phases ◽  
Electron Imaging

The interfacial reactions between solders and under bump metallization (UBM) have been of great interest recently in flip chip technology. Intermetallic compounds (IMCs), i.e., (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4, usually formed between solders and UBM. To fully understand the interfacial reactions and phase transformation phenomenon, a suitable phase diagram concerning solders, IMCs, and UBM materials is required. In particular, a Sn-rich phase region in the Sn–Cu–Ni ternary diagram is very critical in determining the concentration tendency of x and y values in (Ni1−x,Cux)3Sn4 and (Cu1−y,Niy)6Sn5 compounds. In this study, ternary Sn–Cu–Ni alloys were prepared and annealed at 240 °C. Three equilibrium phases, Sn, Ni3Sn4, and Cu6Sn5, were identified by x-ray diffraction analysis and also showed in backscattered electron imaging. Using electron probe microanalysis quantitative analysis, three acme compositions of the ternary region in the Sn–Cu–Ni isotherm near the Sn-rich corner were determined as 98.5 at.% Sn, (Ni0.80, Cu0.20)3Sn4 and (Cu0.59,Ni0.41)6Sn5. In addition, the solubility of Cu and Ni in (Ni,Cu)3Sn4 and (Cu,Ni)6Sn5 compounds was evaluated. Finally, the isothermal section of the ternary Sn–Cu–Ni system at 240 °C was proposed on the basis of experimental results in this study.

Strengthening effect of Zn in heat resistant Mg–Y–Zn solid solution alloys

2003 ◽  
Vol 48 (8) ◽  
pp. 997-1002 ◽  
Author(s):  
M. Suzuki ◽  
T. Kimura ◽  
J. Koike ◽  
K. Maruyama
Keyword(s):  
Solid Solution ◽  
Strengthening Effect ◽  
Heat Resistant

An in situ TEM study of nucleation and growth of the Ω phase in an Al-4.0Cu-0.5Mg-0.5Ag alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 526-527
Author(s):  
A. Garg ◽  
J. M. Howe
Keyword(s):  
Elevated Temperatures ◽  
Cold Water ◽  
Nucleation And Growth ◽  
Age Hardening ◽  
In Situ Tem ◽  
Dislocation Loops ◽  
Ω Phase ◽  
Actual Mechanism ◽  
New Phase

Addition of small amounts of Ag to Al-Cu-Mg alloy with high Cu:Mg ratios stimulates precipitation of a new phase, designated Ω, which has an orthorhombic structure and forms as thin coherent hexagonal plates on {lll} α planes. This phase significantly increases the age hardening characteristics of the alloy, particularly at elevated temperatures. The mechanism of nucleation of Ω phase is not known but is believed to be fundamentally different from that of θ’ and S’ phases which also form in these alloys. The presence of Ag and Mg only in trace quantities makes the problem of finding the actual mechanism of nucleation of Ω phase difficult.An in situ hot stage TEM study was conducted on an Al-4.0Cu-0.5Mg-0.5Ag(wt.%) alloy in order to understand the nucleation and growth behavior of Ω phase. Two types of initial microstructures were used: 1) homogenized, solution-treated and cold water-quenched, 2) as-quenched and aged for 1 hr. at 190°C. The as-quenched structure shown in Fig. 1(a) consists of a high density of small dislocation loops, some helical dislocations and a few straight dislocations. When this foil was heated in the microscope, observable precipitation occured at about 205°C.

An Investigation on Precipitation Behaviour of Cu-Rich Phase in Super304H Heat-Resistant Steel by Three Dimensional Atom Probe

2010 ◽  
Vol 654-656 ◽  
pp. 110-113
Author(s):  
Cheng Yu Chi ◽  
Jian Xin Dong ◽  
Wen Qing Liu ◽  
Xi Shan Xie
Keyword(s):  
Aging Time ◽  
Power Plants ◽  
Three Dimensional ◽  
Atom Probe ◽  
Strengthening Effect ◽  
Resistant Steel ◽  
Heat Resistant Steel ◽  
Rich Phase ◽  
Heat Resistant ◽  
Precipitation Behaviour

Super304H, a Cu-containing 18Cr-9Ni-3CuNbN heat-resisting steel is wildly used as an superheater/reheater tube material for ultra-super-critical (USC) power plants all over the world. It is recognized that the Cu-rich phase is an important strengthening phase for Super304H. However, the detail precipitation behaviour and its strengthening effect are still not very clear. Investigated material was taken from routine production and was aged at 650°C for different times. The precipitation of Cu-rich phase in Super304H was studied by three dimensional atom probe (3DAP) and TEM. Experimental results show that Cu-rich clusters have been formed at very early stage of 650°C aging. The Cu-rich particle images have been clearly caught just after 650°C aging for 5h. The Cu atoms gradually concentrate to Cu-rich particles and the other elements (such as Cr, Ni etc) diffuse away from Cu-rich particles to γ-matrix with the increasing of aging time. The Cu-rich particle size and its density have been determined as a function of aging time. Cu-rich particles still keep nano-size and distribute homogenously in grains even after long time (1,000h) aging, which is one of the most important reasons for keeping good strength of Super304H heat-resistant steel at high temperatures.

Effect of Zn Contents on Microstructure in AZ-Series Magnesium Alloys

2011 ◽  
Vol 409 ◽  
pp. 358-361 ◽  
Author(s):  
Yuichi Narukawa ◽  
Katsumi Watanabe ◽  
Kenji Matsuda ◽  
Tokimasa Kawabata ◽  
Susumu Ikeno
Keyword(s):  
Magnesium Alloys ◽  
Hardness Test ◽  
Alloy System ◽  
Al Alloys ◽  
Age Hardening ◽  
Al Alloy ◽  
Moderate Increase ◽  
Hardening Behavior ◽  
The Matrix ◽  
The Difference

Magnesium alloys containing Al have been used for industrial materials due to their lightweight and recyclability. The Mg-Al alloys are usually used for the industrial production. The Mg-Al alloys are divided into AZ-series alloys with the addition of Zn, and AM-series alloys with the addition of Mn, respectively. The addition of Zn to the Mg-Al alloy system reduces the solid solubility of Al in Mg, increases the amount of precipitate phases after ageing and thus causes a moderate increase in strength. The Mg17Al12phase (γ) is reported as the precipitate formed in the Mg-Al alloys during aging after the solution heat treatment, which is the discontinuous precipitate in the grain boundary and continuous precipitate in the matrix. However, there is few report about the effect of Zn contents on age-hardening behavior and microstructure of AZ-series alloys. The propose of this study is to investigate the difference of the age-hardening behavior and microstructures of AZ-series alloys using hardness test and scanning electron microscopy (SEM) observation.

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