Please consider attending the following:
MATERIALS ENGINEERING
“Mechanical Behavior of Yttria Stabilized Zirconia at Microscale”
By
Jaehun Cho
Purdue MSE Ph.D. Preliminary Exam
Advisor: Professor Xinghang Zhang
ABSTRACT
Yttria stabilized
zirconia (YSZ) has metastable tetragonal phase at room temperature, which can transform into monoclinic phase with ~ 4% volume expansion under an applied external stress. The phase transformation (martensitic transformation) occurs near a crack tip where
the external stress is concentrated and hinders a crack propagation by generating a compressive strain field, thereby enhancing toughness and strength. Recently, it is known that miniaturization of a specimen increases toughness of YSZ by decreasing mismatch
stress among grains during martensitic transformation. Furthermore, it turns out that superelasticity and shape memory effect can be tremendously enhanced by scaling down the specimen. In this study, the concept of martensitic transformation and the factors
affecting its effectiveness will be explored. Also, the mechanical properties of YSZ at macroscale and microscale will be compared. Lastly, the enhanced superelasticity and shape memory effect will be reported.
Date: Thursday, September 28, 2017
Time: 1:30 P.M.
Place: ARMS 1028