Linear expansion coefficient
Sometimes called linear expansivity (linear expansivity), indicating the degree of material expansion or contraction. Divided into a certain temperature point of linear expansion coefficient and a certain temperature range of linear expansion coefficient, the latter is called the average linear expansion coefficient. The former is the elongation of a unit length of material per degree of increase; the average linear expansion coefficient is the average elongation of a unit length of material in a certain temperature range, per degree of temperature increase.