Analysis of Copper-Nickel Alloys: Properties and Microstructure

This report provides a comprehensive analysis of copper-nickel alloys, focusing on their composition, microstructure, and properties. The study begins with an introduction to copper alloys and their applications, specifically in engine cooling systems. It delves into the composition of copper-nickel, highlighting the roles of copper, nickel, and strengthening elements like magnesium. The report examines the microstructure of copper-nickel alloys, discussing crystal structures, grain boundaries, and the use of optical microscopes for observation. It explains alpha and beta phases, as depicted in phase diagrams, along with the influence of deformation and annealing temperatures on the alloy's properties. The report explores how processing methods affect the properties of copper-nickel alloys, emphasizing corrosion resistance and electrical conductivity. It also discusses the structures of copper-nickel alloys, including various material designations and compositions. The manufacturing and processing of copper-nickel are detailed, covering melting, casting, working, heat treatment, machining, and joining techniques. The report concludes with discussions on the elastic modulus, slip systems, and phase diagrams of copper-nickel alloys, along with a list of relevant references.

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TABLE OF CONTENTS
Introduction..................................................................................................................................2
Copper nickel composition..........................................................................................................3
Micro structure of copper nickel..................................................................................................4
Alpha and Beta of copper nickel..................................................................................................6
How the processing of the copper nickel alloy cause a change in properties..............................9
Relationship between the compositions of copper nickel and microstructure and its properties 9
Structures of copper nickel alloys..............................................................................................10
Manufacturing and processing of copper-nickel........................................................................13
Elastic modulus E of copper-nickel...........................................................................................16
Slip systems in hcp.....................................................................................................................17
TI allotropes, phase Diagram of copper-nickel..........................................................................18
Reference...................................................................................................................................19

Introduction
The performance of copper can be extended to suit many high tech products and industrial
applications. Usually this is achieved by alloying process: To come up a solid material out of two
or more different metals. Through the combinations copper with other metals, arrange of copper
alloys can be made to fit almost any application. This study focuses on analyzing an enegine
cooling system made of copper-nickel alloys.
Fig: Copper-nickel engine cooling system1
The combination of nickel and copper greatly improves corrosion resistance and the overall
strength and also retains good ductility2. These copper-nickel alloys possess excellent resistance
to marine corrosion. The chief nickel-copper alloys are 70/30 and 90/10. The 70/30 has greater
resistance to corrosion and much stronger, but the 90/10 will offer good services for many
and the fact that it is to less expensive , it tends to be more widely used3.
1 Bierlein, J.C. and DeHart, A.O., 1983. Score resistance, hardness and performance of diffused copper-
nickel-tin bearings. SAE transactions, pp.159-172.
2 Kumar, A., Wolf, E.E. and Mukasyan, A.S., 2011. Solution combustion synthesis of metal nanopowders:
Copper and copper/nickel alloys. AIChE journal, 57(12), pp.3473-3479.
3 Valdez, B., Schorr, M., Zlatev, R., Carrillo, M., Stoytcheva, M., Alvarez, L., Eliezer, A. and Rosas, N.,
2012. Corrosion control in industry. Environment and Industrial Corrosion, Practical and Theoretical
Aspects.

Copper nickel composition.
Copper-nickel is an alloy of copper elements which consists of nickel and also elements that are
strengthening based like magnesium4. Copper is an element that has a symbol of Cu.It’s a ductile
and malleable element that has very high electric conductivity. The nickel presence in copper
nickel elements makes it very hard and the strength is so high, this reduces the possibility of
corrosion of the element.
In the periodic table, the elements of copper and nickel are adjacent to each other; 29 and 28
respectively and the atomic weight of this elements are63.54 and 68.71 respectively. Copper and
nickel are miscible and soluble in liquid and solid state.
Table: Copper and nickel are miscible and soluble in liquid and solid state5
Fig 1: Showing characteristics of copper nickel.
4 Auwal, S.T., Ramesh, S., Zhang, Z., Yusof, F., Liu, J., Tan, C., Manladan, S.M. and Tarlochan, F., 2019.
Effect of copper-nickel interlayer thickness on laser welding-brazing of Mg/Ti alloy. Optics & Laser
Technology, 115, pp.149-159.
5 Johnson, J.L. and German, R.M., 1993. Phase equilibria effects on the enhanced liquid phase sintering
of tungsten-copper. Metallurgical Transactions A, 24(11), pp.2369-2377.

Fig 2: Showing the strength of
copper nickel6
Micro structure of copper nickel
Microstructure are metals that are in
solid from when they are in
crystalline. The metal structure of the
crystal structure is known as internal
structure and its atomic arrangement is in corresponding lines and sequence7. The usual metallic
objects comprises of polycrystalline. Polycrystalline exhibits many tiny aggregates of the
powdery crystals known as grains. The grain can only be viewed under microscope since they
are tiny aggregates of crystal. Consequently, the optical microscope and metallography, are
always used for observation of these crystal grains. The crystal grains exhibits a corresponding
lines spreads across multiple grains known as annealing twins and they appear like a tiny metal
especially after they are mechanically worked on under high temperature8.
High temperatures may improves and increases the crystallization process hence increasing the
sizes of the crystal of copper nickel and reducing the micro strain, this is because of discharge of
crystalline faults devoid of the process of crystallization in alloys of amorphous9.
6 Austin, R.A. and McDowell, D.L., 2012. Parameterization of a rate-dependent model of shock-induced
plasticity for copper, nickel, and aluminum. International journal of plasticity, 32, pp.134-154.
7 Pham, M.S., Liu, C., Todd, I. and Lertthanasarn, J., 2019. Damage-tolerant architected materials
inspired by crystal microstructure. Nature, 565(7739), pp.305-311.
8 Greer, J.R. and De Hosson, J.T.M., 2011. Plasticity in small-sized metallic systems: Intrinsic versus
extrinsic size effect. Progress in Materials Science, 56(6), pp.654-724.
9 Sudagar, J., Lian, J. and Sha, W., 2013. Electroless nickel, alloy, composite and nano coatings–A critical
review. Journal of alloys and compounds, 571, pp.183-204.

Micro structure helps in providing an information on the composition and processing of the
copper nickel.
Fig 3: Showing the images of micro structure of copper nickel10
Alpha and Beta of copper nickel
This the stage of every process plotted in a form of a diagram representing the solubility of a
copper nickel. The phase diagram shows the connection between temperature and the
composition of the grains at the equilibrium phase11.
The phase of the beta is the part in which the tiny percentage and proportion of A atoms are
softened in the atomic B matrix.
10 Qian, Y., Tan, J., Liu, Q., Yu, H., Xing, R. and Yang, H., 2011. Preparation, microstructure and sliding-
wear characteristics of brush plated copper–nickel multilayer films. Surface and Coatings
Technology, 205(15), pp.3909-3915.
11 Vrsalović, L., Gudić, S. and Kliškić, M., 2012. Salvia officinalis L. honey as corrosion inhibitor for
CuNiFe alloy in sodium chloride solution.

Fig 4: showing binary phase of copper nickel alloy12
The parameters and measurements used in the processing of copper nickel includes:
 Deformation degree
 Annealing temperatures.
Deformation degree
Orientation of copper nickel experiences a lower level of distortion. The copper nickel crystals or
grains are often processed into a tiny and equivalent sizes of grains.
Annealing temperatures
Copper nickel tends to have a resistance property due to the strengthening elements that it
exhibits. Its ability to be resistance to electricity and corrosion is annealed condition is at a given
temperature is influenced by its properties and composition13.
12 Gupta, K.P., 2002. The Cu-Ni-Ti (copper-nickel-titanium) system. Journal of phase equilibria, 23(6),
p.541.
13 Rahmani, K., Jadidian, R. and Haghtalab, S., 2016. Evaluation of inhibitors and biocides on the
corrosion, scaling and biofouling control of carbon steel and copper–nickel alloys in a power plant cooling
water system. Desalination, 393, pp.174-185.

The slime algae adhesion, sea anemones, sea mosses, molluscs (oysters and mussels) and barnacles of
marine structures on surfaces is referred to as bio fouling. It can create an impact on performance of
systems negatively.

How the processing of the copper nickel alloy cause a change in properties

Copper nickel alloy processing change the original copper nickel alloy into
the desired shape, and also improve its properties. The finally processed
copper nickel has modified surface property which protects it against
deterioration. Deterioration may occur through corrosion, oxidation,
deformation or mechanical wear. Special surface properties like electrical
conductivity, reflectivity, insulation, decorative and bearing features are
amongst the features and properties of copper nickel that change once the
metal is processed.
Relationship between the compositions of copper nickel and microstructure and its
properties
Copper nickel tends to be hard and strong, this is because of the presence of nickel and other
strengthening elements such as magnesium that it exhibits.
The ductile and malleable properties that copper nickel alloys possess makes the element to have
good conductivity to electricity as well as has the ability to protect itself from corrosion.
Structures of copper nickel alloys.
Copper-nickel is an alloy of copper containing nickel and strengthening elements like
manganese as well as iron. The copper content is averagely 80%.
Binary copper-nickel alloys occur in solid solution form and they exhibit a structure of face-
centred cubic crystal .Copper nickel has corrosive resistance feature and an improved strength.
Its system is relatively simple.
Copper nickel alloys has more than 10% nickel content.

Fig 1: structure of copper nickels14
Fig 2: Form in which copper nickel exists14.
Material designation
Symbol Number Mean composition (Mass %)
CuNi10Fe1Mn1-C2 CC380H
10 Ni; 1.5 Fe; 1 Mn; max. 1.0 Nb; max. 0.10 Si;
Rem. Cu
14 Hüpf, T., Cagran, C., Kaschnitz, E. and Pottlacher, G., 2010. Thermophysical Properties of Five Binary
Copper–Nickel Alloys. International journal of thermophysics, 31(4-5), pp.966-974.

Material designation
Symbol Number Mean composition (Mass %)
CuNi30Fe1Mn1-C CC381H 30 Ni; 1 Fe; 1 Mn; 0.5 Si; Rem. Cu
CuNi30Cr2FeMnSi-C CC382H 30 Ni, 2 Cr, 1 Fe, 1 Mn, 0,5 Si, 0,25 Ti, 0,15 Zr
CuNi30Fe1Mn1NbSi-
C
CC383H 30 Ni; 1 Fe; 1 Mn; 0.75 Nb; 0.5 Si; Rem. Cu
1A shrinkage value of 1.9 to 2% should be taken into account when making
patterns.
2According to former DIN 17658, for weldable castings: % Nb > 1.55. Si - 0.1
Fig 3: Compositions of copper nickel
Fig 4: Showing applications of copper nickel
The unit cells of two intermetallic compounds: