Fusible alloy is a type of metal that can be melted and used for soldering. It is composed of two or more metals that have been combined to form an alloy with a low melting point. Soldering is a process in which two or more metal pieces are joined together by melting a fusible alloy, such as SOLDER, at the joint. The alloy is heated until it melts and then allowed to cool, forming a strong bond between the two pieces.