Effect of Ag addition on the age hardening and precipitation behavior in an Al-Cu-Li-Mg-Zn-Mn-Zr alloy

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.

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The coprecipitation of Cr3P and Cr in Cu

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105886 ◽

1988 ◽

Vol 46 ◽

pp. 764-765

Author(s):

M.J. Witcomb ◽

U. Dahmen ◽

K.H. Westmacott

Keyword(s):

Orientation Relationship ◽

Interface Structure ◽

Model System ◽

Relative Orientation ◽

Age Hardening ◽

Precipitation Behavior ◽

Solution Treated ◽

Small Needle ◽

Diffraction Patterns ◽

Interface Structures

Cu-Cr age-hardening alloys are of interest as a model system for the investigation of fcc/bcc interface structures. Several past studies have investigated the morphology and interface structure of Cr precipitates in a Cu matrix (1-3) and good success has been achieved in understanding the crystallography and strain contrast of small needle-shaped precipitates. The present study investigates the effect of small amounts of phosphorous on the precipitation behavior of Cu-Cr alloys.The same Cu-0.3% Cr alloy as was used in earlier work was rolled to a thickness of 150 μm, solution treated in vacuum at 1050°C for 1h followed by quenching and annealing for various times at 820 and 863°C.Two laths and their corresponding diffraction patterns in an alloy aged 2h at 820°C are shown in correct relative orientation in Fig. 1. To within the limit of accuracy of the diffraction patterns the orientation relationship was that of Kurdjumov-Sachs (KS), i.e. parallel close-packed planes and directions.

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Enhanced superplasticity in an extruded high strength Mg–Gd–Y–Zr alloy with Ag addition

Journal of Alloys and Compounds ◽

10.1016/j.jallcom.2014.12.036 ◽

2015 ◽

Vol 626 ◽

pp. 309-313 ◽

Cited By ~ 20

Author(s):

A. Movahedi-Rad ◽

R. Mahmudi ◽

G.H. Wu ◽

H.R. Jafari Nodooshan

Keyword(s):

High Strength ◽

Ag Addition ◽

Zr Alloy

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Precipitation Behavior and Strengthening Mechanism of Extruded 2196 Al-Cu-Li Alloy Plate during Multi-Step Age-Hardening Treatment

Journal of Materials Engineering and Performance ◽

10.1007/s11665-021-06310-1 ◽

2021 ◽

Author(s):

Xiaoxue Chen ◽

Haotian Zhang ◽

Guoqun Zhao

Keyword(s):

Strengthening Mechanism ◽

Age Hardening ◽

Precipitation Behavior ◽

Alloy Plate ◽

Hardening Treatment

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Effects of Gd, Y Content on the Microstructure and Mechanical Properties of Mg-Gd-Y-Nd-Zr Alloy

Metals ◽

10.3390/met8100790 ◽

2018 ◽

Vol 8 (10) ◽

pp. 790 ◽

Cited By ~ 4

Author(s):

Changping Tang ◽

Kai Wu ◽

Wenhui Liu ◽

Di Feng ◽

Xuezhao Wang ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Ultimate Tensile Strength ◽

Solution Treatment ◽

Age Hardening ◽

Uniaxial Tensile ◽

Microstructure And Mechanical Properties ◽

Shaped Particle ◽

Zr Alloy ◽

Non Equilibrium

The effects of Gd, Y content on the microstructure and mechanical properties of Mg-Gd-Y-Nd-Zr alloy were investigated using hardness measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and uniaxial tensile testing. The results indicate that the alloys in as-cast condition mainly consist of α-Mg matrix and non-equilibrium eutectic Mg5.05RE (RE = Gd, Y, Nd). After solution treatment, the non-equilibrium eutectics dissolved into the matrix but some block shaped RE-rich particles were left at the grain boundaries and within grains. These particles are especially Y-rich and deteriorate the mechanical properties of the alloys. Both the compositions of the eutectic and the block shaped particle were independent of the total Gd, Y content of the alloys, but the number of the particles increases as the total Gd, Y content increases. The ultimate tensile strength increases as the total Gd, Y content decreases. A Mg-5.56Gd-3.38Y-1.11Nd-0.48Zr alloy with the highest ultimate tensile strength of 280 MPa and an elongation of 1.3% was fabricated. The high strength is attributed to the age hardening behavior and the decrease in block shaped particles.

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