Abstract
This study investigated the effects of particle shape and temperature on the compaction of copper powder at micro scale. Copper powder particles were compressed inside a cylindrical die cavity with 2 mm diameter to form compacts with about 3 mm height. Two kinds of particle shapes, spherical and dendritic, and two forming temperatures, room temperature and 400 °C, were considered in the experiments. Some of the produced compacts were further sintered at 600 °C. The study also used simple upsetting tests to investigate the characteristics of the deformation of the compacts under compressive stresses. The results showed that the compacts produced at room temperature demonstrated brittle deformations. However, by increasing the forming temperature to 400 °C, ductile deformations have been observed on the compacts of dendritic particles. Furthermore, the sintering treatment resulted in increases in dimensions, decreases in relative density and hardness, and an increase in ductility. It also led to pore growths which have been seen on scanning-electron microscope images. These phenomena were most significant in the dendritic powder compacts which were produced at 400 °C and treated by the sintering process.
Highlights
Micro forming processes have been developed in recent years with the objective of fabricating micro metal parts available for the mass production in the fields of electronics products, life science, and transport industry
By using different methods of compressing and shaping, powder metallurgy (PM) has been developed into several processes including cold isostatic pressing (CIP), hot isostatic pressing (HIP), and powder injection molding (PIM)
The effect of the sintering process was more significant in the cases of dendritic particles in which the hardness number decreased to 64 HV at location A for the process at room temperature, and to 46 HV at location C for the process at 400°C
Summary
Micro forming processes have been developed in recent years with the objective of fabricating micro metal parts available for the mass production in the fields of electronics products, life science, and transport industry. The direct laser sintering process of metallic powder, which does not require a compaction of powder, has developed for rapid tooling [2] and producing metallic microstructures [3]. Similar to PIM, micro powder injection molding, which can produce the micro-components of metal, ceramic and hard materials, is an attractive process for the mass production of complex micro-components with features at the micrometer or sub-micrometer scale [5, 6]. Copper powders were compressed inside a cylindrical die cavity to form compacts with 2 mm diameter. The dimension, relative density, hardness, and microstructure of the produced compacts were investigated
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