Difference between revisions of "Dilatant shear bands in solidifying metals"

From Soft-Matter
Jump to: navigation, search
(New page: ==Reference== Gourlay, C.M., Dahle, A.K. ==Keywords== dilatancy, shear, granular media ==Summary== Figure 1. [[Image:Nonlinear_2.jpg |...)
 
Line 13: Line 13:
 
[[Image:Nonlinear_3.jpg |right| |200px| |thumb| Figure 3.]]
 
[[Image:Nonlinear_3.jpg |right| |200px| |thumb| Figure 3.]]
  
The authors study the microstructure of partially solidified alloys under shear.  It is found that these alloys behave similarly to a cohensionless granular material, exhibiting Reynold's dilatancy and strain localization in dilatant shear bands.
+
The authors study the microstructure of partially solidified alloys under shear.  During the solidification of a metallic alloy, it has been shown that after nucleation, crystals are initially dispersed in the liquid and the material behaves as a suspension.  As the crystals grow, the volume fraction of solid, <math>f_s</math> increases, and at a critical value <math>f_s^{Coh}</math>, there is a sharp increase in viscosity due to the formation of a loose solid.  As the metal continues to solidify, partial cohesion between solids develops, allowing the solid to transmit shear, compressive, and tensile strains.  Although metals at high volume fraction have been studied extensively, metals at relatively low volume fractions (<math>f_s^{Coh} \leq f_s \leq 0.5</math>) have not.  This paper deals with dilatancy in this low volume fraction regime.

Revision as of 20:50, 5 December 2009

Reference

Gourlay, C.M., Dahle, A.K.

Keywords

dilatancy, shear, granular media

Summary

Figure 1.
Figure 2.
Figure 3.

The authors study the microstructure of partially solidified alloys under shear. During the solidification of a metallic alloy, it has been shown that after nucleation, crystals are initially dispersed in the liquid and the material behaves as a suspension. As the crystals grow, the volume fraction of solid, <math>f_s</math> increases, and at a critical value <math>f_s^{Coh}</math>, there is a sharp increase in viscosity due to the formation of a loose solid. As the metal continues to solidify, partial cohesion between solids develops, allowing the solid to transmit shear, compressive, and tensile strains. Although metals at high volume fraction have been studied extensively, metals at relatively low volume fractions (<math>f_s^{Coh} \leq f_s \leq 0.5</math>) have not. This paper deals with dilatancy in this low volume fraction regime.