Tungsten Copper High Temperature Liquid Phase Sintering

Tungsten copper high temperature liquid phase sintering is use the tungsten powder and copper powder by mixing, pressing, liquid phase sintering process for the system tungsten copper alloy. Traditional practice is usually higher than the melting point of copper in a high temperature above 300 ℃ densified liquid-phase sintering, characterized by the production process is simple, but there are high sintering temperature, sintering time is long, a large number of volatile copper poor sintering property, low sintered density (only for theoretical density of 90 to 95) and other shortcomings, can not meet the requirements. Therefore, in order to improve the density of the material in the liquid phase sintering after post-treatment processes related to the need to increase multi-pressure, hot, hot forging, etc., but it increases the complexity of the process, the application is limited. AK Bhallal8, who used explosive compaction prepared tungsten copper alloy has good high-temperature liquid phase sintering effect. In addition, the high temperature liquid phase sintering process of discovery, tungsten, copper powder particle size also affects the sintered tungsten-copper composite material density, the finer the powder, the higher the density obtained by sintering.

The performance of the W-Cu Composite materials prepared by different liquid phase sintering methods

Currently, a large number of researches show that as the sol - gel method, spray drying method (thermal chemical synthesis), Machinery thermo chemical synthesis, mechanical alloying method for preparing nanoscale tungsten copper composite powders, reuse special nanocomposite powder sintering activity is expected to obtain high density tungsten-copper composite material provides an effective way. Which was prepared by mechanical alloying of tungsten-copper composite material can not only make mixing ingredients, but also through repeated deformation and rupture of cold welding process makes it extremely refined powder, and the powder milled with a very serious lattice distortion, high the density of defects, and nano-scale layered structure of alternating fine structure, high surface energy-active, has a greater driving force and better sintering properties. Mr. Wang by mechanical alloying combination of powder metallurgy technology to prepare W-20Cu composite outcome surface, with the extension of milling time, the organization W-20Cu sintered body more evenly, Cu phase distribution is more uniform. Density, shrinkage, hardness, bending strength of the sintered body with the milling time increases; 20h thermal conductivity of the composite sintered body milling peak (130.61WM-1K-1), continue milling, thermal conductivity is reduced. Considering all of the findings, W-Cu composite powders prepared by mechanical alloying can be obtained with excellent combination of physical properties of W-20Cu composite.

Overall, the production of high-temperature liquid phase sintering process is simple, but has a high sintering temperature, sintering time is long, a large number of volatile copper, poor sintering performance, lower sintered density and other shortcomings, so the high-temperature liquid phase sintering method can not prepare high density of tungsten copper composite material, if after assisted sintering process makes the process complicated and costly.