Contact reactions of chromium carbide base materials with copper alloys

1985 ◽  
Vol 24 (9) ◽  
pp. 703-707
Author(s):  
A. D. Panasyuk ◽  
V. A. Maslyuk ◽  
V. N. Klimenko ◽  
V. G. Kayuk
Keyword(s):  
Chromium Carbide ◽  
Copper Alloys ◽  
Base Materials

Friction Stir Welding of Copper Alloys by PTA Hardfaced Chromium Carbide Tools

2016 ◽  
Vol 49 (2) ◽  
pp. 70
Author(s):  
A. Baskaran ◽  
K. Shanmugam ◽  
V. Balasubramanian
Keyword(s):  
Friction Stir Welding ◽  
Chromium Carbide ◽  
Copper Alloys ◽  
Friction Stir

Why Gold Flash Can Be Detrimental to Long-Term Reliability

2004 ◽  
Vol 126 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Jingsong Xie ◽  
Ming Sun ◽  
Michael Pecht ◽  
David F. Barbe
Keyword(s):  
Electrical Conductivity ◽  
Stress Relaxation ◽  
Base Metal ◽  
Copper Alloys ◽  
Electrical Contacts ◽  
High Electrical Conductivity ◽  
Electrical Failure ◽  
Base Materials ◽  
Insight Into

Most connectors are made from copper or copper alloys, with beryllium copper and phosphor bronze being the most common base materials due to their high electrical conductivity, low stress relaxation, and competitive cost. The most significant drawback is copper’s low resistance to corrosion, which can lead to electrical failure of connectors. For this reason, a layer of gold is often plated on the surfaces of connectors to seal off the base metal from being directly exposed to the environment. As an economical practice, gold flashing has been used to protect electrical contacts from corrosion. However, there is increasing evidence indicating that gold flashing can be detrimental in applications calling for long-term reliability. This paper provides insight into reliability issues of gold flash.

Friction Stir Welding of Copper Alloys by PTA Hardfaced Chromium Carbide Tools

2016 ◽  
Vol 49 (2) ◽  
pp. 70 ◽  
Author(s):  
A. Baskaran ◽  
K. Shanmugam ◽  
V. Balasubramanian
Keyword(s):  
Friction Stir Welding ◽  
Chromium Carbide ◽  
Copper Alloys ◽  
Friction Stir

scholarly journals Imaging characterization of friction stir welds in the AA 5182-H111 aluminium alloy

2009 ◽  
Vol 15 (S3) ◽  
pp. 81-82
Author(s):  
Rui M. Leal ◽  
Carlos Leitão ◽  
Altino Loureiro ◽  
Dulce M. Rodrigues
Keyword(s):  
Aluminium Alloy ◽  
Frictional Heating ◽  
Copper Alloys ◽  
Base Material ◽  
Soft Materials ◽  
Grain Structure ◽  
Friction Stir ◽  
Fine Grain ◽  
Base Materials ◽  
Dissimilar Welds

AbstractThe environmentally friendly friction stir welding (FSW) process is being increasingly used in joining similar and dissimilar aluminium and copper alloys and other soft materials. In this process a rotating tool promotes significant shear strain and frictional heating of the base materials, in order to stir them into a highly plasticized weld region, at the trailing side of the tool. Due to the intense plastic deformation, complex material flow patterns, such as vortices, swirls and whorls occur during welding. In dissimilar welds, these patterns are readily revealed by differential etching and the respective microstructures characterized. However, in similar welds, such as the welds between plates of AA 5182-H111 aluminium alloy, it is hard to distinguish the different features in the welds and characterize their microstructures. Fig. 1 illustrates optical and TEM micrographs of a weld in this alloy. In the optical image of the weld, at the top of the image, it is possible to distinguish three main areas signalized by numbers: the weld nugget (1), with a very fine grain structure with 2.8 um mean grain size, and a transition region (2) between the nugget and the base material (3), which is usually called the Thermomechanical Affected Zone (TMAZ).

Neutron irradiation scoping study of twenty-five copper-base materials

1987 ◽  
Vol 2 (5) ◽  
pp. 568-579 ◽  
Author(s):  
O. K. Harling ◽  
N. J. Grant ◽  
G. Kohse ◽  
M. Ames ◽  
T-S Lee ◽  
...  
Keyword(s):  
Powder Metallurgy ◽  
Yield Strength ◽  
Copper Alloys ◽  
Pure Copper ◽  
Copper Base ◽  
Base Materials ◽  
Irradiation Test ◽  
Fusion Applications ◽  
Property Changes ◽  
Higher Doses

A scoping irradiation test was carried out to help define the performance of copper-base materials in potential fusion applications. Twenty-five different copper materials including oxide dispersion-stabilized and precipitation-hardened powder metallurgy alloys, as well as pure copper and solid solution-strengthened ingot alloys, were neutron irradiated to 13.5 dpa at 400°C in the Experimental Breeder Reactor II (EBR-II) fast reactor. Volumetric swelling and electrical conductivity data were measured for all irradiated materials, and four selected materials were characterized for mechanical property changes using a miniaturized disk bend test. A number of these copper alloys, especially those prepared by powder metallurgy techniques, showed low swelling (less than 0.3%), small changes in conductivity (less than ± 5%), and relatively small changes in yield strength with good post-irradiation ductility. Preliminary electron microscopy results show microstructural changes that are consistent with the results of the macroscopic studies. The pure copper materials showed significant changes in conductivity and high levels of swelling as a result of the neutron exposure. It is apparent that a variety of copper alloys can survive fast neutron exposures to at least 13.5 dpa at 400°C without unacceptable changes in density, conductivity, or yield strength. Further irradiation testing to much higher doses and experimental investigation of the effect of transmutation product gases are needed to fully define the response of available copper alloys to fusion reactor environments.

scholarly journals Phase Separation and Development of the Microstructure for Stainless Steel to Copper Alloy Weld Joints Using a Fiber Laser

2019 ◽  
Author(s):  
Sheila Medeiros de Carvalho ◽  
Rafael Humberto de Mota Siqueira ◽  
Milton Sergio Fernandes de Lima
Keyword(s):  
Stainless Steel ◽  
Phase Separation ◽  
Copper Alloys ◽  
High Heat ◽  
Rocket Engines ◽  
Base Materials ◽  
Secondary Precipitation ◽  
Laser Welds ◽  
Hardness Values ◽  
Alloy Weld

Stainless steel and copper alloys joints are often applied in aerospace, marine and power industries where both high thermal and electrical conductivity (Cu) and corrosion resistance (steel) are required. In the aerospace industry, in particular for the combustion chamber of rocket engines, copper and steel combinations offer perfect materials selection due to their combined high thermal conductivity and good stiffness. In this work, laser welds were produced with intensity between 3.8 × 104 and 5.7 × 104 W/mm2 and a heat input between 72 and 108 J/mm, giving an aspect ratio of 1.8. The microstructure of the weld beads was marked by chemical heterogeneities due to the phase separation between Cu and Fe in the liquid state. The phase separation gave rise to globular precipitates which further transform due to a secondary precipitation at temperatures below 1000 °C. The steel side part of the weld presents around 20% Cu, leading to a liquation of the grain boundaries and cracking at high heat inputs. The hardness values situated between both base materials and the tensile shear behavior, when the weld is sufficiently tough, present strength up to 350 MPa and elongation up to 10%.

Morphology and atomic structure of segregated grain boundaries in Cu-Sb

1992 ◽  
Vol 50 (1) ◽  
pp. 254-255
Author(s):  
R. W. Fonda ◽  
D. E. Luzzi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Intergranular Fracture ◽  
Atomic Structure ◽  
Copper Alloys ◽  
Polycrystalline Materials ◽  
Grain Boundary Embrittlement ◽  
Boundary Embrittlement

The properties of polycrystalline materials are strongly dependant upon the strength of internal boundaries. Segregation of solute to the grain boundaries can adversely affect this strength. In copper alloys, segregation of either bismuth or antimony to the grain boundary will embrittle the alloy by facilitating intergranular fracture. Very small quantities of bismuth in copper have long been known to cause severe grain boundary embrittlement of the alloy. The effect of antimony is much less pronounced and is observed primarily at lower temperatures. Even though moderate amounts of antimony are fully soluble in copper, concentrations down to 0.14% can cause grain boundary embrittlement.

TEM study of a biofilm on copper corrosion

1996 ◽  
Vol 54 ◽  
pp. 220-221
Author(s):  
W. A. Chiou ◽  
N. Kohyama ◽  
B. Little ◽  
P. Wagner ◽  
M. Meshii
Keyword(s):  
Marine Bacterium ◽  
Culture Medium ◽  
Copper Alloys ◽  
Pure Copper ◽  
Localized Corrosion ◽  
Natural Seawater ◽  
Copper Corrosion ◽  
New Approach ◽  
The Past ◽  
Copper Tolerant

The corrosion of copper and copper alloys in a marine environment is of great concern because of their widespread use in heat exchangers and steam condensers in which natural seawater is the coolant. It has become increasingly evident that microorganisms play an important role in the corrosion of a number of metals and alloys under a variety of environments. For the past 15 years the use of SEM has proven to be useful in studying biofilms and spatial relationships between bacteria and localized corrosion of metals. Little information, however, has been obtained using TEM capitalizing on its higher spacial resolution and the transmission observation of interfaces. The research presented herein is the first step of this new approach in studying the corrosion with biological influence in pure copper.Commercially produced copper (Cu, 99%) foils of approximately 120 μm thick exposed to a copper-tolerant marine bacterium, Oceanospirillum, and an abiotic culture medium were subsampled (1 cm × 1 cm) for this study along with unexposed control samples.

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