The Role of the Si Network to the Stabilization of Hardening Precipitates in the Al-Mg-Si(-Cu) Alloy System

2012 ◽  
pp. 279-284
Author(s):  
Flemming J. H. Ehlers ◽  
Sigurd Wenner ◽  
Sigmund J. Andersen ◽  
Calin D. Marioara ◽  
R. Holmestad
Keyword(s):  
Alloy System ◽  
Cu Alloy

The Role of the Si Network to the Stabilization of Hardening Precipitates in the Al-Mg-Si(-Cu) Alloy System

2012 ◽  
pp. 279-284
Author(s):  
Fleming J.H. Ehlers ◽  
Sigurd Wenner ◽  
Sigmund J. Anderson ◽  
Calin D. Marioara ◽  
R. Holmestad
Keyword(s):  
Alloy System ◽  
Cu Alloy

Solidification Mechanisms in the Sn-Cu-Ni Lead-Free Solder System

2010 ◽  
Vol 654-656 ◽  
pp. 1381-1384 ◽  
Author(s):  
Tina Ventura ◽  
Young Hee Cho ◽  
Arne K. Dahle
Keyword(s):  
Binary Alloys ◽  
Alloy System ◽  
Lead Free Solder ◽  
Complex Phase ◽  
Wave Soldering ◽  
Ni Alloys ◽  
Cu Alloy ◽  
Free Solder ◽  
Ni Additions

Pb-free solders based on near-eutectic Sn-0.7Cu-xNi alloys provide excellent solderability during wave soldering with cost advantages compared to Ag-containing alternatives. However, there is only limited knowledge of the solidification mechanisms in this alloy system and, furthermore, the ternary Sn-Cu-Ni phase diagram is not yet fully established. In this study, unidirectional solidification has been conducted in a Bridgman furnace using both binary alloys from the Sn-Cu6Sn5 system and ternary Sn-rich Sn-Cu-Ni alloys. The influence of Ni additions on the solidification mechanisms is assessed by comparing the microstructures of the ternary and binary alloys. The results are used to discuss the contrasting Sn-Cu-Ni phase diagrams reported in the literature. The results demonstrate the complex phase relations in the Sn-Cu alloy system, and the important role of trace amounts of various solute elements.

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.

scholarly journals Accelerated discovery of high-strength aluminum alloys by machine learning

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Jiaheng Li ◽  
Yingbo Zhang ◽  
Xinyu Cao ◽  
Qi Zeng ◽  
Ye Zhuang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Aluminum Alloys ◽  
Mechanical Performance ◽  
High Strength ◽  
Cost Effective ◽  
Alloy System ◽  
Processing Route ◽  
Specific Strength ◽  
Cu Alloy ◽  
High Strength Aluminum Alloys

Abstract Aluminum alloys are attractive for a number of applications due to their high specific strength, and developing new compositions is a major goal in the structural materials community. Here, we investigate the Al-Zn-Mg-Cu alloy system (7xxx series) by machine learning-based composition and process optimization. The discovered optimized alloy is compositionally lean with a high ultimate tensile strength of 952 MPa and 6.3% elongation following a cost-effective processing route. We find that the Al8Cu4Y phase in wrought 7xxx-T6 alloys exists in the form of a nanoscale network structure along sub-grain boundaries besides the common irregular-shaped particles. Our study demonstrates the feasibility of using machine learning to search for 7xxx alloys with good mechanical performance.

Evolution of Twin-Related Variants of α Phase in a Ti-V-Cu Alloy

2011 ◽  
Vol 172-174 ◽  
pp. 481-486 ◽  
Author(s):  
Hoi Pang Ng ◽  
Colleen J. Bettles ◽  
Barry C. Muddle
Keyword(s):  
Electron Microscopy ◽  
Early Stage ◽  
Twin Plane ◽  
System A ◽  
Cu Alloy ◽  
Α Phase ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
Isothermal Ageing

The precipitation of a-phase has been investigated in a concentrated b-alloy of the Ti-V-Cu system. a-precipitates in geometrically coupled forms were developed in the alloy when subject to isothermal ageing at 500°C. High-resolution transmission electron microscopy (HRTEM) revealed that a-phase embryos tend to nucleate in a symmetrical manner directly from an early-stage solute-partitioned diffusional product. The a-precipitates so developed constitute twin-related variants characterized by a twin plane lying on one of the {0111}a planes. The results are discussed with respect to the role of Cu on the formation of heterogeneous nucleation sites for a-phase.

Growth and characterization of Al–Cu–Li quasicrystals

1988 ◽  
Vol 3 (2) ◽  
pp. 233-237 ◽  
Author(s):  
J. M. Parsey ◽  
H. S. Chen ◽  
A. R. Kortan ◽  
F. A. Thiel ◽  
A. E. Miller ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Alloy System ◽  
Icosahedral Phase ◽  
Solidification Velocity ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Pseudobinary Phase Diagram ◽  
Melt Composition

The alloy system Al–Li–Cu was investigated extensively over the composition range 5.8–8 Al–Cu–3Li to develop a detailed understanding of the formation and properties of the icosahedral phase, known as T2. Material from the various charges was analyzed by optical and electron microscopy, energy dispersive x-ray analysis, differential thermal analysis, and differential scanning calorimetry. The role of the melt composition and the solidification velocity were found to be crucial in determining the micro- and macrostructure and the existence of the icosahedral phase. A pseudobinary phase diagram for the region around Al6CuLi3, is presented based on these analyses. Based on this phase diagram the largest single icosahedral crystals of Al5.1CuLi3 yet reported, with diameters greater than 1 cm, were produced by Bridgman methods.

The synergistic role of the support surface and Au–Cu alloys in a plasmonic Au–Cu@LDH photocatalyst for the oxidative esterification of benzyl alcohol with methanol

2020 ◽  
Vol 22 (3) ◽  
pp. 1655-1664 ◽  
Author(s):  
Xiaoyu Wang ◽  
Ruiyi Wang ◽  
Jie Wang ◽  
Chaoyang Fan ◽  
Zhanfeng Zheng
Keyword(s):  
Benzyl Alcohol ◽  
Support Surface ◽  
Acid Base ◽  
Base Pairs ◽  
Oxidative Esterification ◽  
Cu Alloy ◽  
Cu Alloys

The acid–base pairs of the support synergistic with Au–Cu alloy NPs could drive the oxidative esterification of benzyl alcohol with methanol.

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