CBSE Class 10 Answered

Alloys are a mixture of a pure metal with one or more other metals or nonmetallic substances (carbon, etc.) in correct proportions that are selected to provide desirable properties for strength, fabrication and resistance to heat as well as resistance to electric current. The alloying matter may be a small amount of the total alloy but should affect the crystals of the pure metal including grain size and matter between grain boundaries. The discovery of ductile tungsten made it possible to use it in heating elements, including light bulb filaments. It was necessary to exclude oxygen and carbon from the pure tungsten to avoid embrittlement, etc.