Explanation

A method for determining the thermal expansion properties of materials by dilatometer. When the sample deviates from the room temperature (20 ° C), the ratio of its length change to the length at room temperature is called the thermal deformation rate (ALAL) of the sample materials at the temperature difference (AT). The thermal expansion property is usually expressed as a function of thermal deformation rate temperature. When the thermal deformation rate changes linearly with temperature, the average linear expansion coefficient can be used to characterize the thermal expansion performance of materials: the average volume expansion coefficient g of isotropic materials is approximately equal to 3a. Thermal expansion properties can be used to study the structure, phase transformation and critical phenomena of solid materials. It is used in solid state physics, physical metallurgy, metallographic heat treatment and metallurgy. The key to widely applied testing in structural design and other aspects is to accurately measure the small deformation variables of the sample using a dilatometer. Secondly, the sample temperature is accurately measured and controlled through temperature measurement and control devices. The dilatometer consists of the above two parts and the soaking pit, recording and data processing devices. Its core is a dilatometer. The main types of dilatometers include differential type, grating rod type, optical interference type, direct measurement type, and capacitive type. The optical interferometric dilatometer has the highest accuracy among them. But the structure is complex. The differential dilatometer is the most widely used. Direct measurement expansion juice can be used for non-contact measurement.

Classification