Heat Treatment Effect to Properties and structure of Molybdenum Foils
Molybdenum foil products are widely used in electronic industry. During the process by 20 rolls foil milling machine, molybdenum foil will increase its hardness. At the same time, as thickness reducing, the processing deformation and dislocation interaction rise gradually. Therefore, molybdenum foil finally has a result of an increase in the deformation resistance and a decrease in its plasticity.
In the end, these mechanical changes can affect the working performance expected by the final users.
Thereby, we need to do the heat treatment on molybdenum foil to eliminate machining hardened, improve the microstructure and increase the plasticity. These thermal treatments help the molybdenum foils have good microstructure and properties, and consequently ensure the molybdenum foils meet users’ requirements.
The Heat Treatment of Molybdenum Foils
When vacuum annealing furnace anneals the molybdenum foils, the heat treatment temperature is between 750 ~ 1 000 ℃, 750 ℃, 800 ℃, 850 ℃, 900 ℃, 950 ℃, 000 ℃, separately.
The annealing period is 50 mins on each temperature, along with the cooling process after out of the furnace.
Temperature is the main thermodynamic condition for crystallization. Therefore, no matter in the nucleation or sub crystallization stage, the crystal nucleus can only grow by consuming the high energy generated in the deformation. The crystal core generates polygons by climbing and sliding, which 
greatly reduces the crystal distortion. By doing so, we can achieve to increase the strength and decrease the plasticity. The larger the deformation is, the lower the crystallization temperature can be.
The Degree of Crystallization Affects the Properties of Molybdenum Foil
The mechanical properties of molybdenum foil are affected by different heat treatment and different heat treatment systems.
The Effect of Heat Treatment Systems To Molybdenum Foil Mechanical Properties
As the temperature rising under a 750 ~ 800 ℃, the strength of molybdenum foil starts to reduce. The elongation of the foil increases gradually. In the temperature of 850 ~ 900 ℃ environment, foil begins to crystallize and accelerate the decline of its strength. At the same time, the elongation of the foil increases remarkably. As a result, the heat treatment significantly improves the plasticity. In the temperature of 950 ~ 1 000 ℃ environment, molybdenum foil starts to fully crystallize. At this point the grains begin to grow and coarsen. Although there is no significant reduction in the strength of the foil, but the elongation of the foil reduces dramatically. Thus, the plasticity of the foil begins to fail.
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