Sintering Deformation by nyut545e2

VIEWS: 21 PAGES: 3

									                        Sintering Deformation
Following sub-projects are undergoing:

 1. Finite element analysis of sintering deformation using master sintering
    curve instead of a full constitutive law

 2. Predicting maximum heating rate for sintering ceramic components

 3. Predicting microstructural evolution and macroscopic deformation of bio-
    glass forms taking into account of glass crystallisation.

 4. Multi-scale modelling of sintering

Their details are as following

1. Finite element analysis of sintering deformation using master
   sintering curve instead of a full constitutive law

Collaborators: Dr Julie Yeomans, University of Surrey;
               Dr Philippe Blanchart, Ecole Nationale Supérieure de
               Céramique Industrielle, France

PhD Student: Mr. Sasan Kiani

Project description: Various forms of constitutive laws have been developed
for the finite element analysis of sintering. Some of these were developed
based on micromechanical models and the others based on empirical fittings
with experimental data. The mechanism-based constitutive laws differ from
each other widely; it is difficult to know which one to use. On the other hand,
obtaining fitting functions in an empirical constitutive law is very time
consuming. In this project we have developed a finite element scheme which
does not require a full constitutive law but only the densification data (density
as function of time) in order to predict sintering deformation. The
densification data can be derived from the master sintering curve of the
powder material. Different sintering mechanisms and nonlinearity pose no
difficulty to the method. The densification based finite element analysis
(DFEA) follows the shape evolution of a sintering component from a given
initial shape and density distribution.




     Fig. 1. A comparison between our finite element prediction and experimental
     measurement of sintering deformation.
2. Predicting the optimised heating rate for sintering ceramic
   components

Postdoctoral Research Fellow: Dr Ruoyu Huang

Project description: Ceramics manufactures have to rely on trial and error to
determine the optimised heating rate in their sintering cycle. We are
developing a software package to integrate the heat transfer analysis, sintering
deformation analysis and failure analysis to predict the optimised heating rate
for sintering sophisticated ceramic components.

3. Predicting microstructural evolution and macroscopic
   deformation of bio-glass forms during sintering taking into
   account of glass crystallisation.

Collaborator: Dr Aldo Boccaccini, Imperial College

Postdoctoral Research Fellow: Dr Ruoyu Huang

Project description: Bio-glass forms have been sintered to make bioactive
scaffolds for tissue engineering at Imperial. The sintering process is controlled
by viscous deformation of the glass but complicated by crystallisation which
may occur simultaneously. In this project we are developing a multi-scale
modelling technique to predict the microstructural evolution and the
macroscopic deformation of the glass form in order to optimise the processing
parameters for different applications.

4. Multiscale modelling of sintering

Co-investigators: Professor Alan Cocks (University of Oxford)
                  Professor Saiful Islam (University of Bath)
                  Dr Julie Yeomans (University of Surrey)

Postdoctoral Research Fellow: Dr Ruoyu Huang
PhD Student: Mr Lifeng Ding

Project description: Sintering is a process in which powder compacts are fired
and consolidated into strong solid. Almost all ceramic products and an
increasing number of metal, polymer and glass products are made by
sintering. Accurately predicting the shrinkage and microstructure of sintered
products is very useful to manufactures. However modelling sintering is one
of the most challenging problems in material modelling. Sintering
deformation is fundamentally linked to microstructural evolution and
depends on very subtle changes in microstructure and chemistry, sometimes
at the atomic level. Consequently, the ability of prediction by the current
generation of sintering models is poor. On the other hand, this challenge
provides us with an ideal platform for integrating modelling techniques at the
atomistic, particle and continuum levels. Bringing together multi-scale
elements to create an integrated sintering model is the theme of this project.
For the first time, the integrated model is able to take chemical impurity,
doping, particle/pore size distribution, agglomeration and anisotropy into
consideration. The compaction-sintering interface will take compaction
history into consideration. Together these will form the next generation of
sintering models with much improved ability of prediction. The mathematical
techniques developed will also have a widespread and long-term influence on
the materials engineering community.

								
To top