Centrifugal casting of metal matrix composites. Ph.D. Thesis
Metal matrix composites (MMCs) have excellent properties and low material costs, but high manufacturing costs. The primary difficulty in manufacturing MMCs is in forming a tight matrix/reinforcement bond. This dissertation investigates improving the matrix/reinforcement bond through the use of high centrifugal forces. High centrifugal forces promote fiber infiltration (or particle submergence), remove gas voids, and resist particle pushing by the solidification front. Several aluminum matrix MMC samples are formed at up to 2,660 g`s. The project involves: (1) design and construction of a rotating crucible capable of a 690 C, 2,600 g-force environment; (2) a finite differences heat transfer model using an unique technique (spreadsheet iteration) which has application to engineering teaching and simple modeling problems; (3) a bubble buoyancy/surface adhesion analysis to predict maximum surface voids or bubble cling in cast materials; (4) a fluid surface tension effects analysis evaluating particle submergence into a melt, and melt infiltration into a porous media such as a fiber form; (5) creation of samples and direct visual measurement of void sizes in agreement with bubble buoyancy/surface adhesion theory; (6) performance of tests and direct evidence supporting the developed particle submergence/porous media infiltration theories; and (7) creation of samples and direct measurement of material strength under subjection to bending stress. The final conclusion is that use of high centrifugal forces in MMC manufacturing has potential, however it is only useful for large diameter fibers or particles (on the order of 200 micron) and relatively high g-forces (on the order of 2,500 g`s).
- Research Organization:
- Univ. of California, Berkeley, CA (United States)
- OSTI ID:
- 237287
- Report Number(s):
- N-96-22402; NIPS-96-34129; TRN: 9622402
- Resource Relation:
- Other Information: TH: Ph.D. Thesis; PBD: Jan 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
IACMI Project 4.2: Thermoplastic Composite Development for Wind Turbine Blades
Level-set Modeling Simulations of Chemical Vapor Infiltration for Ceramic Matrix Composites Manufacturing