Explanation

Also called full density and 100% relative density, it refers to the density of dense materials with the same material as powder metallurgy. Most powder metallurgy materials contain pores, and their density values are lower than those of materials of the same material. For convenience, it is specified that the density of the material without voids is the theoretical density. For non porous materials structural parts, the higher the relative density, the better. Because pores are the fracture source of materials, hot forming technology appeared in modern powder metallurgy, and its density value can reach or approach the theoretical density value. For example, materials such as hot isostatic pressing powder high speed steel, high temperature alloy, titanium alloy and so on, their relative density can reach 99.99%. The relative density of HIP hardmetal can reach 99.999%, which is very close to the theoretical density. The theoretical density can be calculated by the content percentage of each component; However, it is often used to determine the full density sample made of the same materials by melting as the standard. According to the theoretical density, powder metallurgy materials can be divided into formed metal (10%), porous materials (20% -40%), conventional pressing sintered parts (80% -90%), and hot formed powder materials (close to 100% of the theoretical density value).

Classification