Materials which can be changed in shape and size when exposed to a
magnetic field are called magnetostrictive materials. The magnetostrictive material
was developed for use in the many actuator industries. A single crystal of
magnetostrictive material is used to maximize its magnetostrictive response. It can
be produced by the crystal growth method. However, a single crystal from this
method is limited in size and shape. The growth direction of a single crystal,
sometimes, is different from its magnetostrictive axis.
Capacitor discharge welding (CDW) is a high power density welding
process at 10���-10��� Kelvin/second. The fusion zone of CDW is very small and the
heat affected zone of CDW is rarely detectable. The amount of material affected by
heat in the welding process is very small. The objective of this study is to use
capacitor discharge welding (CDW) to join single crystal copper and determine the
effect of CDW on the microstructure of the single crystal copper.
To minimize the cost of using single crystal copper, low oxygen copper
C101 (polycrystalline) is used as a replacement. By maximizing the weld strength,
Response Surface Methodology (RSM) is used to find the optimum condition of
single crystal copper.
The single crystal copper was cut at different orientations and welded
together with the one that had same orientation to compare the results. The
metallography was used to study voids, fusion zone and dislocations of the single
crystal copper after welding.
After analyzing the effect of the CDW process on the single crystal, the
effect of crystal orientation upon void formation was found statistically
inconclusive. Small fusion zone as 0.09154 mm was found. No heat affected zone
of single crystal was detected. Also, no microstructural damage was found along
the fusion zone. Dislocation density before and after CDW were not different
because there was no statistically significant difference between the etch pit density
in the fusion zone and that outside the fusion zone.
In summary, regardless of voids, CDW may be a useful method for
welding single crystal metals. / Graduation date: 1999
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/34009 |
| Date | 15 March 1999 |
| Creators | Thaneepakorn, Wiwat |
| Contributors | Paul, Brian K. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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