1-15 of 15 Search Results for

curvature undercooling

Follow your search
Access your saved searches in your account

Would you like to receive an alert when new items match your search?
Close Modal
Sort by
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005207
EISBN: 978-1-62708-187-0
... lateral growth to cover the TiB 2 , further growth must be outward, as illustrated in Fig. 12 . The solid aluminum takes the form of a growing spherical cap. At a given undercooling, growth ceases when the radius of curvature reaches r cr for the undercooling, as given by Eq 12 . As the undercooling...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005210
EISBN: 978-1-62708-187-0
... constitutionally supercooled region ahead of the columnar front. Since the stable dendrite tip growth requires a balance between the constitutional supercooling and curvature effects, a constitutionally undercooled zone is always present ahead of the dendrite tip. Equiaxed growth can occur if the required...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005209
EISBN: 978-1-62708-187-0
... and dendrites. Clearly, in order to form such an undulated interface structure, the system requires energy for creating the curvature that must come from interface undercooling. Not every structure is possible, and the strength of the CU defines the possible curvature (λ -1 ). Fig. 5 Image of a...
Book Chapter

Series: ASM Handbook
Volume: 3
Publisher: ASM International
Published: 27 April 2016
DOI: 10.31399/asm.hb.v03.a0006225
EISBN: 978-1-62708-163-4
... imposes fixed contact angles, leading to a curvature of the solid-liquid interface. This curvature is thermodynamically disadvantageous. Because the contact angles are material constants, this curvature is higher when the lamellar spacing is small. Fig. 17 Surface tension balance at the three-phase...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005226
EISBN: 978-1-62708-187-0
... is its own heat sink. This occurs when the alloy is undercooled below its liquidus temperature prior to the initiation of solidification. The release of latent heat can then be absorbed by the sample itself, a process that is quite efficient but may cause a reheating (recalescence) of the sample...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005227
EISBN: 978-1-62708-187-0
... premelted film induced changes in the curvature of the solidification front underneath the particle (i.e., becomes more concave), which promoted engulfment of the particles. Garvin and Udaykumar ( Ref 47 , 48 ) computationally examined the drag force acting on the particle as it is approached by the front...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005236
EISBN: 978-1-62708-187-0
... between the solidifying mush and liquid. Applying a kinetic model for the motion of this boundary then determines the growth of the grain structure. The liquid outside a grain envelope has to stay in an undercooled state until the local REV is captured by a growing envelope, or an appropriate nucleation...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005406
EISBN: 978-1-62708-196-2
... boundary then determines the growth of the grain structure. The liquid outside a grain envelope has to stay in an undercooled state until the local REV is captured by a growing envelope, or an appropriate nucleation condition is fulfilled. The PF method, finally, uses the PF variable Φ( x,t ) as an...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005215
EISBN: 978-1-62708-187-0
... requires that there must be (1) negligible undercooling before the nucleation of the solid phases; (2) negligible undercooling at the solid-liquid interface due to curvature, interface kinetics, or a solute boundary layer (local equilibrium at the solid-liquid interface); (3) sufficient mass transport in...
Series: ASM Handbook
Volume: 3
Publisher: ASM International
Published: 27 April 2016
DOI: 10.31399/asm.hb.v03.a0006223
EISBN: 978-1-62708-163-4
... all temperatures ( Fig. 15a , b ). When Δ H mix > 0, however, the situation is more complicated. At high temperatures, T Δ S mix is greater than Δ H mix for all compositions and the free-energy curve has a positive curvature at all points ( Fig. 15c ). On the other hand, at low temperatures...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005240
EISBN: 978-1-62708-187-0
... role because of the creation of the solid/liquid interface area. Also, during solidification, a decrease in the equilibrium melting point produces a positive undercooling and is associated to the solid/liquid interface curvature, which is usually convex toward the liquid phase. This curvature effect is...
Series: ASM Handbook
Volume: 4E
Publisher: ASM International
Published: 01 June 2016
DOI: 10.31399/asm.hb.v04e.a0006250
EISBN: 978-1-62708-169-6
... have a finite interfacial energy. The material still is metastable, with thermodynamic stability being achieved only if the structure becomes a single grain or crystal. In contrast to recrystallization, the boundary moves toward its center of curvature. Some of the grains grow, but others become...
Book Chapter

Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005323
EISBN: 978-1-62708-187-0
... controlling factor remains the rate at which the solidification is proceeding. The rapid solidification favored by thin section sizes or highly conductive molding media can result in undercooling. Undercooling can cause the solidification to start at a temperature lower than the expected eutectic temperature...
Series: ASM Handbook
Volume: 4B
Publisher: ASM International
Published: 30 September 2014
DOI: 10.31399/asm.hb.v04b.a0005950
EISBN: 978-1-62708-166-5
... undercooling below the martensite start temperature (M s ), are widely used. However, there are several other models that are reported to produce better predictions for several steels ( Ref 161 ). For diffusion-controlled phase transformations (ferrite, pearlite, bainite, austenite), the transformation is...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006778
EISBN: 978-1-62708-295-2