1993 Fiscal Year Final Research Report Summary
Growth Mechanism of Dendritic Secondary-Arms and Microsegregation
| Project/Area Number |
04650627
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
金属加工(含鋳造)
|
|---|
| Research Institution | Nagaoka University of Technology |
|---|
Principal Investigator |
MIYATA Yasunori Nagaoka University of Technology Professor, 工学部, 教授 (50016177)
|
|---|
| Project Period (FY) |
1992 – 1993
|
| Keywords | Dendrite / Micrisegregation / Melt flow / Primary-arm / Secondary-arm / Growth theory / Stability of interface |
|---|
| Research Abstract |
The growth mechanism is investigated experimentally and theoretically for dendritic arms.
(1) Experimental apparatus for the dendritic growth under melt flow is built up, and the growth rate and tip radius of curvature of dendrite are measured in the undercooled solidification of succinonitrile melt. The growth rate increases with the increase of melt flow for a given undercooling. THe natural convection in the melt is estimated to affect the growth as strong as the forced flow velocity 1 mm.
(2) Migration of bubbles in melt, which will be accidentally included in the melt and will affect the growth of dendrite. is studied. Migration is observed in the microgravity condition. A bubble moves under temperature gradient from the cold place to the hot place by Marangoni convection. Therefore, the migration will contribute to destabilize the interface of dendrite in the solidification of undercooled melt.
(3)A dendritic growth theory, which includes self-consistently the marginal stability of the interface, is proposed. It takes into account the growth along the interface, which is induced by the conservation of the flux of heat through the interface. The predictions and experiments are successfully compared for the growth rate and the tip radius of curvature for the dendrite in undercooled solidification of succinonitrile.
|
