It is desirable to produce a copper-nickel alloy that has a minimum noncold- worked tensile strength of \(380 \mathrm{MPa}(55,000 \mathrm{psi})\) and a ductility of at least \(45 \%\) EL. Is such an alloy possible? If so, what must be its composition? If this is not possible, then explain why.

To answer this question, we have to analyze the Copper-Nickel phase diagram and locate specific regions where such an alloy is possible. We are considering two properties: tensile strength and ductility.

In general, there is a trade-off between strength and ductility, i.e., as the strength of an alloy increases, its ductility decreases. Therefore, we are looking for an alloy composition that strikes a balance between the two desired properties.

Based on the phase diagram and the relationship between strength and ductility, we need to identify the range of possible Cu-Ni compositions that can meet our requirements.

Once we have the range of possible compositions, we need to analyze each one and check if they satisfy the minimum strength and ductility requirements mentioned in the problem statement. If we are able to find at least one composition that satisfies the requirements, then the desired alloy is possible, and we can provide the composition as the answer. Otherwise, we shall explain that such an alloy is not possible. To get a detailed answer, it is necessary to consult the Copper-Nickel phase diagram and the mechanical properties of copper and nickel alloys. Due to the limited information provided in the question and the absence of a provided phase diagram, it is impossible to precisely answer this question. However, the suggested steps can guide you in solving such problems with the required data.