Transformations ductility improvement

In T1-6AI-4V, hot ductility is improved, and a ductility trough becomes narrow when rapidly cooled from the region. In the more hardenableTl-6AI-6V-2Sn alloy, excellent ductility is obtained down to 700 °C (1290 °F) in the sensitized mode. The reheated mode produces poorer ductility than the sensitized mode, and ductility improves more in alloys that exhibit more retardation of the p to a transformation on cooling. Sensitized specimens were quenched from 1200 °C (2190 °F) to the test temperature. Strain rate was 5/s. 

The NiAl phase in NiAl alloys with second Fe-rich and/or Ni-rich phases is off-stoichiometric with an Al deficiency. Thus NiAl in these alloys may transform martensitically, as has been discussed in Sec. 4.3.2, which offers a further possibility for improving the strength and ductility. Indeed such alloys with martensitically transformable NiAl exhibit some room temperature tensile ductility (Khadi-kar etal., 1987 Furukawa etal., 1988 Ishida etal., 1991a Kainuma etal., 1992 b). It is noted that these alloys show a shape memory effect and are of interest in view of respective applications. 

In [ 1991 Par] the cast iron containing small contents of Cu and Mo was studied aiming to improve mechanical properties. Phase transformations during heat treatment and flieir influence on strengfli, ductility and fracture toughness were established. 

Plasticizers are frequently incorporated to improve the workability of polymers, but often transform a rigid plastomer into a soft and ductile material. From early times, camphor was used to plasticize nitrocellulose and yield celluloid. Today plasticizers are most common in soft PVC, while unplasticized rigid PVC is also extensively used. Plasticizers may consist of liquids or solids (oils, esters or prepolymers). They are characterized by an extremely low glass-transition temperature, weakening the secondary bond strength in low-crystalline polymers with which they form a solid solution phase. 

---