Synthesizing and characterization of Cu-WC-Si composite prepared by using planetary ball milling
Cu-WC-Si composites were synthesized by using a planetary ball milling. Different composition of elemental Cu, WC and Ti powders were mixed and milled for 5 and 10 hours in an open air. The powder characterized before and after milling to expose the effect of milling variables on particle size, homogenization and contamination. Analyzing carried out by using X-ray and scanning electron microscope (SEM). The as milled particle size and homogenization generally influenced by milling time and tungsten Carbide (WC) content. With longer milling time and higher tungsten carbide content, particle size becomes smaller and smaller. The average particle sizes of the as milled powder are in ranged from 5µm to 30 µm and strongly depend on the copper content.
Densification behavior of tungsten-fiber-reinforced copper powder compacts under hot isostatic pressing
Densification behavior of tungsten-fiber-reinforced copper powder compacts under hot isostatic pressing was investigated. Hot isostatic pressing was carried out for a bundle of copper-coated tungsten fibers in copper powder. Due to tungsten-fibers and copper coating layers, the densification rate of a tungsten-fiber-reinforced copper powder compact was slower than that of pure copper powder. The constitutive equations by McMeeking and co-workers and by Abouaf and co-workers were implemented into a finite element program (ABAQUS) to analyze densification behavior of tungsten-fiber-reinforced copper powder compacts under hot isostatic pressing. Finite element calculations were compared with experimental results for the variation of relative density with time for copper powder compacts during hot isostatic pressing. Density distributions in copper powder compacts were also investigated by comparing experimental results with finite element calculations.
Determining the Jaw Relationship
Contacts between the upper and lower posterior teeth of complete dentures take place during the opening and closing strokes of mastication (Brudvik and Howell 1990). These contacts are fast, gliding impacts of the mandibular teeth which contact close to the position of maximal intercuspation of the teeth, called the “intercuspal occlusion”. The intercuspal position is the position adopted by the mandible when the teeth are in intercuspal occlusion.