Summer report 2017
University of California, Irvine Materials Science and Engineering Department PhD candidate
Kenta Ohtaki

This is going to be the last year of my PhD program. My PI and I agreed that I will be done by
next spring quarter 2018. I was planning to done before winter 2017 but instruments that I wasgoing to use were delayed and my PI wants me to TA her class in the winter quarter 2018, so I
decided to finish writing my thesis by the end of this year and use the extra three month forwrapping up and job hunting.
This is my 5th year and I will be done in 4.5 years since I started in fall 2013. I have gained somany skills and connections, not to mention knowledge in different fields and I can feel
confidence in me which I did not have enough when I first started the PhD program. I would liketo talk about what I have been up to and what I think is really important to pursue a PhD degree.
In my last report I mentioned that I had conferences lined up after coming back from the researchin Germany. After those conferences, I felt that I can take a break from attending conferences fora while since data collection and analysis have been busy and attending conferences takes time
not just the conferences themselves but also to prepare for them. So I told my PI that the next
conference is going to be my last conference before I graduate, which is going to be International
Conference and Expo on Advanced Ceramics and Composites in Florida on January 21-26 2018.
I will be presenting my work on radiation damage behavior in multiphase ceramics (YSZ, A 2O3and MgAl2O4) using 1 GeV Au ions. The results from the samples irradiated in Germany isfinally put together showing very interesting behaviors. When accelerated ions enter ionicmaterials, they interact with electrons and nuclei of the target material generating defects in thecrystals. By using X-ray diffraction and electron microscopy, the damage can be quantified andvisually observed. X-ray result is showing that the lattice of the ceramic materials expanded withincreasing dosage but the amount of expansion in the multiphase sample was smaller than single
phase materials suggesting that having multiple phases enhanced radiation damage tolerance.
The theory for this is that the interfaces between dissimilar phases is disordered allowing defects
to be annihilated more easily than at grain boundaries in single phase materials. This work can berelated to the earlier work of mine with Si ion irradiation which will be submitted for publication
soon. I will spend this whole summer finishing up with data collection so that I can concentrateon analysis during fall.
In the course of a PhD program, I have seen and experienced various obstacles and I will morethis year for sure. I have seen several friends dropping out of their PhD program and finish witha master’s degree and I also have seen new PhD students and candidates coming in for 4 years sofar. Seeing them and look back at myself and my colleagues, I think dedication is the mostimportant component to finish a PhD program. If you are not sure about what you are doing andif you doubt that the career path you are taking does not suit you, you won’t be able to stay in thePhD program because you will face so many obstacles and your strong will can only allow youto overcome those. Almost every single grad students are stressed about their projects and want
to be done with them but a lot of them genuinely love what they are doing and that is what stressthem because we seek the answers so hard. Dedication also makes students self-motivated which
I see a lot in new students. Every time new PhD students come in for rotations, I can almost tell
who will find matching group and who won’t. Most rotation students are treated as a burden
because majority of them will not yield any resourceful data during their rotation period.
Therefore most of times, they are left to themselves not knowing what to do. Those who come tosenior students asking if they can come with us to observe what we are doing and those who arewilling to learn new things are more likely to success in their PhD program. This sounds reallyobvious but it is difficult to do and easy to do otherwise. Motivation is what drives you and what
people in the academia would like to pick up and I believe it comes from your dedication. I did
not think I will be so deeply in love with the field I am in now but thanks to that, I think I cansurvive in any career path as long as I can stay in materials science field.
I am excited to report more good news in the next report.