A comparison of experimental time-secondary dendritic spacing and coarsening models for Al-Si-Cu alloys

2020 ◽  
Vol 54 ◽  
pp. 14-18 ◽  
Author(s):  
Bruno Donadoni ◽  
Guilherme Lisboa de Gouveia ◽  
Amauri Garcia ◽  
José Eduardo Spinelli
Keyword(s):  
Dendritic Spacing ◽  
Experimental Time ◽  
Cu Alloys

The influences of macrosegregation, intermetallic particles, and dendritic spacing on the electrochemical behavior of hypoeutectic Al-Cu alloys

2007 ◽  
Vol 70 (11) ◽  
pp. 928-937 ◽  
Author(s):  
Wislei R. Osório ◽  
José E. Spinelli ◽  
Alexandre P. Boeira ◽  
Célia M. Freire ◽  
Amauri Garcia
Keyword(s):  
Electrochemical Behavior ◽  
Dendritic Spacing ◽  
Cu Alloys ◽  
Intermetallic Particles

Corrosion Resistance of Al-Cu Alloys in Function of the Microstructure

2014 ◽  
Vol 783-786 ◽  
pp. 100-107 ◽  
Author(s):  
Alejandra Silvina Román ◽  
Claudia Marcela Méndez ◽  
Alicia Esther Ares
Keyword(s):  
Electrochemical Impedance ◽  
Solidification Process ◽  
Directionally Solidified ◽  
Dendritic Spacing ◽  
Cu Alloys ◽  
Al2cu Phase ◽  
Electrochemical Parameters ◽  
Strength Alloy ◽  
Columnar To Equiaxed Transition ◽  
Set Up

Aluminum and its alloys are characterized by low density, high electrical and thermal conductivity, and good resistance to corrosion in certain media such as air. The mechanical strength alloy is achieved. The objective of the present research consist on studying the type of structure (columnar, equiaxed or with columnar to equiaxed transition, CET) using parameters of the solidification process and electrochemical parameters in Al, Cu and Al-Cu alloys with different concentrations. In order to obtain columnar, equiaxed and CET structures, the alloys were directionally solidified upwards in an experimental set up with a set of thermocouples in the samples which permit to determine the time dependent profiles during the process. The electrochemical studies of the samples were realized by using an electrochemical impedance spectroscopy (EIS) technique and potentio-dynamic polarization curves immersed in 3% NaCl solution at room temperature. In general, we observed that the susceptibility to corrosion of the different structures depends on the size of the secondary dendritic spacing and the proportion of Al2Cu phase and Al-rich phase.

Plastic deformation of θ ' in Al-4%Cu alloy

1978 ◽  
Vol 36 (1) ◽  
pp. 576-577
Author(s):  
Shrikant P. Bhat
Keyword(s):  
Deformation Behavior ◽  
Room Temperature ◽  
Electron Microscopic Observation ◽  
Bulk Alloy ◽  
Electron Microscopic ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Orowan Mechanism ◽  
The Subject ◽  
Cyclic Straining

deformation behavior of Al-Cu alloys aged to contain θ ' has been the subject of many investigations (e.g., Ref. 1-5). Since θ ' is strong and hard, dislocations bypass θ ' plates (Orowan mechanism) at low strains. However, at high strains the partially coherent θ ' plates are probably sheared, although the mechanism is complex, depending on the form of deformation. Particularly, the cyclic straining of the bulk alloy is known to produce gross bends and twists of θ '. However, no detailed investigation of the deformation of θ ' has yet been reported; moreover, Calabrese and Laird interpreted the deformation of θ ' as largely being elastic.During an investigation of high temperature cyclic deformation, the detailed electron-microscopic observation revealed that, under reversed straining conditions, θ ' particles are severely distorted--bent and twisted depending on the local matrix constraint. A typical electronmicrograph, showing the twist is shown in Fig. 1. In order to establish whether the deformation is elastic or plastic, a sample from a specimen cycled at room temperature was heated inside the microscope and the results are presented in a series of micrographs (Fig. 2a-e).

Precipitation in Al-Li-Cu Alloys

1981 ◽  
Vol 39 ◽  
pp. 44-45
Author(s):  
J. E. O'Neal ◽  
K. K. Sankaran
Keyword(s):  
Electron Microscopy ◽  
Age Hardening ◽  
Precipitation Behavior ◽  
Zone Formation ◽  
Specific Strength ◽  
Hardening Behavior ◽  
Cu Alloys ◽  
High Specific Strength ◽  
Transmission Electron ◽  
Structural Applications

Al-Li-Cu alloys combine high specific strength and high specific modulus and are potential candidates for aircraft structural applications. As part of an effort to optimize Al-Li-Cu alloys for specific applications, precipitation in these alloys was studied for a range of compositions, and the mechanical behavior was correlated with the microstructures.Alloys with nominal compositions of Al-4Cu-2Li-0.2Zr, Al-2.5Cu-2.5Li-0.2Zr, and Al-l.5Cu-2.5Li-0.5Mn were argon-atomized into powder at solidification rates ≈ 103°C/s. Powders were consolidated into bar stock by vacuum pressing and extruding at 400°C. Alloy specimens were solution annealed at 530°C and aged at temperatures up to 250°C, and the resultant precipitation was studied by transmission electron microscopy (TEM).The low-temperature (≲100°C) precipitation behavior of the Al-4Cu-2Li-0.2Zr alloy is a combination of the separate precipitation behaviors of Al-Cu and Al-Li alloys. The age-hardening behavior at these temperatures is characteristic of Guinier-Preston (GP) zone formation, with additional strengthening resulting from the coherent precipitation of δ’ (Al3Li, Ll2 structure), the presence of which is revealed by the selected-area diffraction pattern (SADP) shown in Figure la.

Imaging of Al-Li-Cu alloys with a Scanning Ion Microprobe

1990 ◽  
Vol 48 (2) ◽  
pp. 314-315
Author(s):  
K.K. Soni ◽  
D.B. Williams ◽  
J.M. Chabala ◽  
R. Levi-Setti ◽  
D.E. Newbury
Keyword(s):  
Mass Spectrometry ◽  
Secondary Ion Mass Spectrometry ◽  
Equilibrium Phase ◽  
Icosahedral Symmetry ◽  
Ion Microprobe ◽  
X Ray ◽  
Cu Alloys ◽  
Two Phases ◽  
The University ◽  
Secondary Ion

In contrast to the inability of x-ray microanalysis to detect Li, secondary ion mass spectrometry (SIMS) generates a very strong Li+ signal. The latter’s potential was recently exploited by Williams et al. in the study of binary Al-Li alloys. The present study of Al-Li-Cu was done using the high resolution scanning ion microprobe (SIM) at the University of Chicago (UC). The UC SIM employs a 40 keV, ∼70 nm diameter Ga+ probe extracted from a liquid Ga source, which is scanned over areas smaller than 160×160 μm2 using a 512×512 raster. During this experiment, the sample was held at 2 × 10-8 torr.In the Al-Li-Cu system, two phases of major importance are T1 and T2, with nominal compositions of Al2LiCu and Al6Li3Cu respectively. In commercial alloys, T1 develops a plate-like structure with a thickness <∼2 nm and is therefore inaccessible to conventional microanalytical techniques. T2 is the equilibrium phase with apparent icosahedral symmetry and its presence is undesirable in industrial alloys.

A STUDY OF G.P. ZONES IN Al-Cu ALLOYS BY ATOM-PROBE FIM

1986 ◽  
Vol 47 (C2) ◽  
pp. C2-171-C2-177 ◽  
Author(s):  
T. HASHIZUME ◽  
K. HONO ◽  
Y. HASEGAWA ◽  
K. HIRANO ◽  
T. SAKURAI
Keyword(s):  
Atom Probe ◽  
Cu Alloys

Onset of Θ' to Θ Phase Transformation in Al-Cu Alloys

2019 ◽  
Author(s):  
Patrick Shower ◽  
James R. Morris ◽  
Dongwon Shin ◽  
Lawrence F. Allard ◽  
Balasubramaniam Radhakrishnan ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Cu Alloys
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