• Korean Journal of Materials Research
• /
• v.5 no.1
• /
• pp.132-139
• /
• 1995

Tnermomechanical treatment consisting of homogenizing, hot and warm rolling were introduced to Al-MgCu-Mn alloys for obtaining superplasticity. The factors affecting the superplasticity of the alloys were investigated by optical and transmission electron microscopy. Large particles which had not been decomposed during homogenizing treatments remained stable in the hot and warm rolling processes. These particles were a source of cavitation and poor elongation in superplastic deformation. On the other hand, fine precipitates were produced during thermomechanical processing, and resulted in improvement of superplasticity by stabilizing microstructure. Two-step homogenizing and air cooling process was more effective than onestep homogenizing and furance cooling process in removing microsegregations and producing fine particles.

• 한국전자현미경학회:학술대회논문집
• /
• 1995.12a
• /
• pp.29-30
• /
• 1995

• 기계와재료
• /
• v.4 no.3 s.13
• /
• pp.63-73
• /
• 1992

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1996.05a
• /
• pp.90-90
• /
• 1996

• Defense and Technology
• /
• no.10 s.92
• /
• pp.11-17
• /
• 1986

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1997.05a
• /
• pp.80-80
• /
• 1997

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1992.05b
• /
• pp.47-47
• /
• 1992

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1996.05a
• /
• pp.107-108
• /
• 1996

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.10a
• /
• pp.59-59
• /
• 2007

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.17 no.4
• /
• pp.1-7
• /
• 2008

Fine grained superplastic Zn-22%Al alloy was extruded using a laser machined micro-die to produce a micro-gear shaft. Extrusion process was conducted under a constant pressure at constant temperatures ranging from 503 to 563K. Laser machining was capable to machine a micro-die with close tolerances and adequate surface quality. The extrusion rate increased with extrusion load under constant extrusion temperature. The rate reached a steady state and became constant after a certain period. There was a small instantaneous stroke on application of the load and then a very brief primary stage which preceded steady-state flow. The micro-extrusion process was proven to produce a micro-gear shaft successfully using a fine grained superplastic Zn-22%Al alloy.