Nickel Alloys — Composition of Monel Metal Identify the nominal composition of Monel metal among the following choices.

Introduction / Context:
Monel is the trade name for a family of nickel–copper alloys renowned for seawater corrosion resistance, good strength, and excellent toughness over a wide temperature range. Recognising Monel's composition helps distinguish it from other nickel alloys like Inconel (Ni–Cr–Fe) and Incoloy (Ni–Fe–Cr), which serve different applications.

Given Data / Assumptions:

• We compare approximate, nominal compositions as typically quoted in handbooks.
• Minor additions (iron, manganese, silicon, etc.) may be present in small amounts.
• We focus on the classic Monel 400-type chemistry.

Concept / Approach:
Monel alloys are primarily nickel and copper. A typical nominal composition for Monel 400 is roughly 67–70% Ni, 28–34% Cu, balance minor elements. Therefore, the option with 68% nickel, 29% copper, and about 3% other elements correctly represents Monel. Options rich in chromium are characteristic of Inconel or stainless-like nickel alloys, not Monel.

Step-by-Step Solution:
Identify Ni–Cu pair as the signature of Monel.Match approximate percentages: ~68% Ni and ~29% Cu aligns with Monel 400.Eliminate Ni–Cr and Ni–Fe–Cr compositions as non-Monel families.

Verification / Alternative check:
Commercial datasheets for Monel 400 list Ni about 63–70% and Cu about 28–34%, confirming the selected option.

Why Other Options Are Wrong:
Ni–Cr or Ni–Cr–Fe mixtures are Inconel/Incoloy types, not Monel.50% Ni–50% Fe corresponds to a different alloy family (permalloys), not Monel.

Common Pitfalls:
Assuming all high-nickel alloys are interchangeable; chemistry dictates corrosion resistance and high-temperature performance.

Final Answer:
68% nickel, 29% copper and 3% other constituents