Admiralty Metal

Admiralty Metal is an alloy primarily composed of copper (71%), zinc (28%), and trace amounts of tin and iron. It is commonly used for heat exchangers and condenser tubes in marine applications due to its excellent corrosion resistance. When Admiralty Metal undergoes a phase change from molten state to solid state, it experiences a significant contraction or shrinkage.

Reasons for shrinkage:
There are several factors that contribute to the shrinkage of Admiralty Metal during solidification:

1. Thermal contraction: As the molten metal cools down and solidifies, it undergoes thermal contraction. This is a natural phenomenon observed in most materials when they transition from a higher temperature to a lower temperature. The contraction occurs due to the decrease in average atomic or molecular vibrations, leading to a reduction in the interatomic or intermolecular spacing.

2. Solidification shrinkage: During solidification, the liquid metal transforms into a solid with a more compact arrangement of atoms or molecules. This rearrangement results in a decrease in volume. The solidification shrinkage is primarily attributed to the change in the crystal structure and the packing density of the atoms or molecules.

3. Phase transformation: The solidification of Admiralty Metal involves the transformation of the liquid phase into a solid phase. This phase change is accompanied by a decrease in volume due to the differences in the atomic or molecular arrangements between the liquid and solid states. The phase transformation can lead to a significant shrinkage as the material transitions from a more disordered liquid state to a more ordered solid state.

Comparison with other metals:
Among the given options, Admiralty Metal (option B) exhibits the most significant shrinkage from molten state to solid state. This is because of its composition and the nature of its phase transformation. Cast iron (option A), brass (option C), and cast steel (option D) also undergo shrinkage during solidification but to a lesser extent compared to Admiralty Metal.

In summary, Admiralty Metal experiences a significant shrinkage during solidification due to factors such as thermal contraction, solidification shrinkage, and phase transformation. These factors contribute to the overall decrease in volume as the molten metal transforms into a solid state.