The elasticity of a material is affected by the following factors: 

(i) Effect of temperature: On heating, mostly the elasticity of materials decreases.

(ii) Effect of impurities: Depending upon the nature of impurity, the elasticity of materials may increase or decrease.

(iii) Annealing: Annealing decreases the elasticity of materials.

(iv) Hammering and rolling: This process increases the elasticity of materials. 

Note: Annealing is a heat process where a metal is heated to a specific temperature /colour and then allowed to cool slowly. This softens the metal which means it can be cut and shaped more easily. Iron rod is heated till it turns red-hot.