Undercooling and glass formation in pulsed-laser melted. gamma. -TiAl

Conference · Fri Jan 01 00:00:00 EST 1988

OSTI ID:6747860

Perepezko, J H; Follstaedt, D M; Peercy, P S

Pulsed laser irradiation of a metallic surface is perhaps the most effective method available for generating ultrarapid liquid quench rates. Associated with the high quench rate is a rapid resolidification as the liquid-solid interface is driven back to the surface upon termination of the laser pulse. Since the unmelted substrate is an excellent heat sink, the movement of a melting temperature isotherm across the near surface is extremely rapid with rates approaching 100 m/s. The velocity of the solidification front, V, in response to the rapid heat transport is governed by the frequency of net atom transfer from the liquid configuration to the crystalline solid configuration. For pure components and dilute single-phase alloys, solidification is believed to be collision limited so that it proceeds as fast as required for the heat flow. In concentrated alloys with solidification into multiple solid phases, diffusional redistribution of solute limits the resolidification rate to far below the collision-limited range. In this case, the liquid can be undercooled to well below the equilibrium solidification temperature, which permits metastable phase nucleation or glass formation. With diffusion-limited resolidification, pulsed laser annealing can be used to access a number of microstructural options. 14 refs., 2 figs.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6747860
• Report Number(s): SAND-88-1475C; CONF-881155-1; ON: DE88016745
• Resource Relation: Conference: Fall meeting of the Materials Research Society, Boston, MA, USA, 28 Nov 1988; Other Information: Paper copy only, copy does not permit microfiche production
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM COMPOUNDS
CRYSTALLIZATION
TITANIUM COMPOUNDS
CRYSTAL-PHASE TRANSFORMATIONS
LASER POWER TRANSMISSION
LASERS
MELTING
METALLIC GLASSES
METALLURGY
NUMERICAL DATA
SOLIDIFICATION
DATA
INFORMATION
PHASE TRANSFORMATIONS
POWER TRANSMISSION
TRANSITION ELEMENT COMPOUNDS
360102* - Metals & Alloys- Structure & Phase Studies
360104 - Metals & Alloys- Physical Properties