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Creep resistance and fracture tolerance are considered two essential aspects to look at for material selection and optimization in high-temperature applications. Materials with extensive industrial applications must inherit adequate immune against creep such that operating temperatures can be raised to maximize performance ensuring a long service life of the equipment. The creep study of cupronickel (CuNi) alloy has become crucial because cupronickel alloys are enticing candidates for high-temperature applications. Nevertheless, the fundamental understanding of creep deformation in cupronickel alloys is still obscure. Herein, we executed classical Molecular Dynamics (MD) simulations to reveal the nature of creep characteristics of cupronickel alloy at a molecular level. In particular, we investigated the thermal and mechanical properties of nanocrystalline (NC) Cu, Ni, and Cu0.5Ni0.5 alloy. As the Cu content in the alloy is raised from 0 to 100%, the steady-state creep rate (SSCR) exhibits a ∼12% increment. Based on our MD simulations, we found that the SSCR of Cu0.5Ni0.5 alloy speeds up dramatically under elevated stress, temperature, and decreasing grain size. Our MD results also reveal that at low stress, the governing creep process is the confluence of lattice diffusion, grain boundary diffusion, and grain boundary sliding, while at high stress, the governing creep mechanism turns into dislocation dominated. Admittedly, our computational analysis will help acquire fundamental insights into the creep mechanism of NC cupronickel alloy, which is crucial for the successful usage of this alloy in corrosive, high stress, and high-temperature applications.

Cupronickel alloys such as 70/30 Cu-Ni have excellent resistance to sea water corrosion and anti-fouling properties, and thus have been widely used for naval and offshore applications. Traditionally, arc welding and brazing processes have been used to weld such materials. In contrast, laser beam welding is a promising technology due to its high productivity, good process flexibility and reliability, and good welding integrity. In the present work, a high power fiber laser system is used to weld 5-mm thick 70/30 Cu-Ni alloy plates in a configuration of butt joints. Then, the laser welded joints are evaluated in terms of microstructures, defects, and mechanical properties (hardness, face and root bend, and tensile) in accordance with the applicable International Organization for Standardization and Defence Standard specifications. Keywords: Laser welding, Cupronickel alloy, Butt joint, Microstructure, Tensile properties, Bend testing

The chapter begins with introduction of different types of copper and copper alloys used in practice. Different types of heat treatments employed for the materials are listed and discussion on individual process, viz. homogenization, annealing after cold working is made. The effect of these heat treatments on changes in structure and properties and the reasons thereof are explained in detail. The stress relieving operation carried out with cold worked materials is also narrated. After discussing the generic issues, heat treatment of important alloys is individually narrated. Following this, the heat treatment of various bronzes is enumerated in detail. Besides these, the critical heat treatment of other copper alloys like chromium copper, zirconium copper, and chromium–zirconium–copper alloys are described with highlights of criticalities in heat treating these important alloys. Separately elaborate discussion is made of the different heat treatment of nickel alloys. Annealing, stress relieving, and cold work followed annealing of conventional nickel alloys are highlighted. That nickel alloyed with Al, Nb, Ti, and Si is capable of precipitation hardening is illustrated with specific examples. Data regarding heat treatment and the consequent properties of copper and nickel alloys are furnished in the form of tables. Due scientific explanations are provided where ever felt necessary.

Copper is used for its high electrical and thermal conductivity, good corrosion resistance, machinability, strength, and ease of fabrication. It can be welded, brazed, or soldered. Brasses are alloys of copper and zinc, and bronze refers to any copper alloy without zinc. Cupronickel alloys contain up to 30% nickel and are always single-phase alloys.

This chapter summarizes stress corrosion cracking of copper and copper-based alloys in different chemical, thermal, and electrochemical environments. The chapter begins with description of different copper-based alloys and their common application. A description of different operating SCC mechanisms for the copper-based alloys is provided. Information regarding the chemical, thermal and electrochemical conditions that could induce SCC of the copper and copper-based alloys and additional details on the SCC mechanism of particular copper-based alloys in specific chemical conditions are also detailed. The role of secondary phase particles on SCC of copper-based alloys is discussed. SCC mitigation strategies for the copper-based alloys are discussed. A summary of the chapter is provided in the end. The aim of this chapter is to develop an understanding of SCC susceptibility of different copper-based alloys in different chemical environments.