Modeling and Experimental Studies of Densification Rates in Current Activated Densification

Master of Science, Graduate Program in Mechanical Engineering
University of California, Riverside, June 2011
Dr. Javier Garay, Chairperson

Current  Activated  Pressure  Assisted  Densification  (CAPAD)  techniques  have shown great promise in efficiently consolidating a wide range of materials systems. This efficiency manifests itself in the form of a high densification rate, which is influenced by the   processing   parameters   and   material   properties.   To   better   understand   these influences,  a  wide  range  of  materials  were  densified  using  the  CAPAD  technique.  By calibrating the device, it was possible to eliminate the effects of thermal expansion and determine the true densification rate of the materials. This data was examined in order to   determine   the   effect   that   pressure   and   homologous   temperature   have   on densification rate as well as their sensitivity to material bonding type.

When  processing  new  materials  using  the  CAPAD  technique,  there  is  often confusion  as  to  what  processing  parameters  will  result  in  full  density.  A  model  was developed to shed light on this issue. This model uses the familiar sigmoidal shape of the  density-temperature  relationship  for  the  CAPAD  along  with  two  model  parameters that are defined by processing conditions as well as material properties. It is hoped that this  model  will  be  able  to  save  future  CAPAD  workers  both  time  and  resources  by allowing them to more accurately estimate their required processing temperature.