2016年3月16日星期三

The importance of powder structure for the properties of powder metallurgy products


Powder production is the first step in manufacture of powder metallurgy, along with the continuous development and improvement of the manufacture of powder metallurgy, in order to meet the requirements of all walks of life of powder metallurgy, powder production method and powder metallurgy products are more and more, and various properties of the powder in the powder metallurgy manufacturing have following several: properties of the powder consists of powder physical properties, chemical composition, process, properties and powder structure, in which the powder structure, including the internal structure and external structure. The structure of the powder has a direct effect on the other properties of the powder and the properties of the powder metallurgy products.

From the point of view of the external structure of the powder, the powder particles have developed outer surface and inner surface. The outer surface can be seen on the surface, including all of the surface of the particle surface of the convex and concave parts and the width of the depth of the crack. The inner surface of the inner wall of the depth including more than the width of the cracks, joints and micro granules and the outer surface of the connected pores and cavities etc..


From the internal structure of the metal powder, and the majority of non metal particles are formed by grain composition. May be single crystal particles, can also be a polycrystalline structure. The actual structure of the particle is more complex than the same crystal structure of dense material. Grain growth in powder production conditions are not sufficient, polar crystals is not complete, will lead to the original powder after crushing, grinding, grain deformation and destruction. Will affect the quality and chemical composition of powder.

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