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What makes indium useful in low-melting alloys?

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A color-coded periodic table of the elements displays each element's symbol and atomic number, with categories such as alkali metals, noble gases, halogens, transition metals, and actinoid elements distinguished by different background colors. — boron group element Modern version of the periodic table of the elements (printable).

Indium is a valuable component in low-melting alloys because it helps create fusible materials that melt at precise temperatures. These alloys are specifically utilized in safety-critical applications, such as fusible plugs, fire-door links, and sprinkler heads, where they act as thermal fuses to detect or control fire.12

Beyond their low melting points, these alloys are prized for their dimensional stability. Depending on the specific combination of metals used, they can be engineered to expand, shrink, or remain stable upon solidification, making them useful for specialized tasks like holding complex objects during machining or serving as temporary supports in pipe bending.2