Measuring device and method of melting volume expansion ratio/molten state density of material

Abstract

The invention discloses a measuring device and a method of melting volume expansion ratio / molten state density of a material, the device is characterized in that a sample chamber is positioned in an electrically heated sample seat; a thermocouple, a PID intelligent temperature controller and a relay are used for coordinately controlling a heating temperature and a heat preservation period; and a probe is fixed on a clamping mechanism and is capable of integrally and freely moving in a z direction along a guide rod. The method comprises the steps of: vertically putting the sample chamber holing samples with a known mass in the sample seat, covering a top cover, guaranteeing the probe to be vertical to the bottom surface of the sample chamber through a correcting device, filling a shielding gas, turning on a temperature display switch, setting a heating parameter and heating; closing the shielding gas after the sample is completely molten, stretching the probe in the sample chamber to measure a liquid level, and stopping the heating procedure to finish one measurement process; repeatedly measuring to obtain an average liquid level, figuring out a melting volume expansion ratio (a negative value refers to melting volume shrinkage) and a molten state density of the sample according to a formula.

Description

technical field [0001] The invention relates to the field of measuring the coefficient of thermal expansion of materials, in particular to the field of measuring the volume expansion rate and the density of the molten state after the material undergoes a solid-liquid phase transition. Background technique [0002] Thermal expansion coefficient is one of the important thermophysical properties of materials. In a crystal with a thermodynamic temperature above 0K, the atoms vibrate thermally near the equilibrium position. As the temperature increases, the vibration energy increases, and the amplitude and frequency increase. However, the potential energy curve is asymmetrical with respect to the initial equilibrium position of the atomic distance, and the attenuation of atomic kinetic energy is smaller in the direction of increasing the atomic distance than in the direction of decreasing the atomic distance, so the distance between the vibrational equilibrium positions increase...

AI Technical Summary

Problems solved by technology

However, the above two methods are limited to solid materials, and the latter’s commercial products have a maximum measurement temperature of 700°C, complex devices and operations, and expensive equipment

It is currently difficult to measure the volume expansion rate of solid materials when they are heated and melted into liquids

Although some researchers (Jurgen Blumm, Jack B Henderson) have designed a device that can measure the volume change rate of metal melting from solid to liquid by improving the ejector rod thermal dilatometer, but not only the structure of the device is complicated, but also the sample container is required to be sealed relative to the liquid metal , The container size must be very accurate and other conditions, which are difficult to meet at hundreds or even thousands of degrees Celsius

Images