CORRELATION OF THERMAL, TENSILE AND CORROSION PARAMETERS OF Zn-Al ALLOYS WITH COLUMNAR, EQUIAXED AND TRANSITION STRUCTURES

ALICIA E. ARES; LILIANA M. GASSA; SERGIO F. GUEIJMAN; CARLOS E. SCHVEZOV

San Francisco, California, USA.

Simposio; SHAPE CASTING: THIRD INTERNATIONAL SYMPOSIUM; 2009

The Minerals, Metals and Materials Society

The columnar to equiaxed transition (CET) has been examined in different wrought and casting alloys  for many  years  and  the metallurgical  significance  of  CET  has  been  treated  in  several articles.  Experimental  observations  in  the  literature  have  focused  on  thermal  parameters  like cooling  rate,  velocity  of  the  liquidus  and  solidus  fronts,  local  solidification  time,  temperature gradients  and  recalescence.  The  objective  of  the  present  research  consist  on  studying  the influence  of  solidification  thermal  parameters  on  the  type  of  structure  (columnar,  equiaxial  or with  the  CET)  and  on  the  secondary  dendritic  spacing  in  Zn-Al  alloys  (Zn-1%Al  and  Zn-4wt%Al, weight percent). Also,  correlate  the  thermal and  structural parameters of  these alloys with tensile and corrosion behavior. The results show that Zn-4wt%Al alloys are more resistant to  the  corrosion  that  Zn-1wt%Al,  independently  of  the  structure.  Also,  in  both  alloys  the equiaxed structures presented a better tensile resistance than the columnar and CET zones.