To say mechanical engineer Dr Veronica Gray loves a challenge is an understatement. Through her research, she is figuring out when, why and how materials break, pushing the breaking point further so materials can better handle extremes.
Gray likes to push the envelope and then some, saying “things only break for one reason — the bonds that hold the atoms together fail”. Her work at Queensland University of Technology’s Centre for Materials Science is focused on nickel superalloys, titanium alloys, MAX phase ceramics, and different types of high-performance steel.
Throughout her career, Gray has worked on ships’ machinery, jet engines and gas turbines.
“You never get the same problem twice, which is really interesting. I work beyond the standard conditions and push beyond our current understanding of the material,” she said.
“When you go beyond the known rules you have to create the rules, and that is what is great about my work. The crazier the challenge, the better.”
Gray’s work involves predicting the breaking point of materials years into the future. For jet engines, this is five years of the most extreme stresses and temperatures. For power generation, this can mean trying to predict 20 years into the future.
“The bonds [in materials] break at different times and in different ways, depending on stress and temperature,” Gray explained. “When we use plants or machines, we bet our lives on the relationship between atoms.”
As the world is in constant flux, Gray is focused on how materials respond to changing patterns in their use, from constant operation to start-stop.
“In the 20th century, we turned technology on and left it running, but in the 21st century it’s not the same,” she said.
“Now everything’s on-demand, and materials are difficult to understand and test because of this. And things break a lot faster for a whole new set of complicated inter-related reasons.”
The interesting part, Gray said, is how much we don’t know about how things break and what they’re going to do.
“We know very little about the impact of using technology on a start-stop or on-demand basis. When we build power stations, we’re making our best guess based on our past experience,” she explained.
“As the world has changed beyond what we understand, in some ways, maintenance and high vigilance is currently what is preventing major failures.”
Pushing boundaries
One of the biggest challenges, Gray said, is to understand the difference between constant operation and non-constant operation in terms of material creep — slowly stretching over time — and fatigue or cracking. Her research explores creep, transient creep, fatigue and thermo-mechanical fatigue.
While pushing boundaries is what excites Gray about her work, she has encountered a few unwelcome problems within her field. The issues that women in engineering face are well documented, and Gray is no stranger to standing out.
“I’ve worked in places where the only other women in the building were in admin. And it’s not unusual to attend a conference of 300 where only two or three are women,” she said.
Her advice for other women engineers is simple: “If you wouldn’t buy that person a cup of coffee, then stop worrying about what that person thinks.”
Gray comes from a military family, which influenced her choice of career. That and coming first in engineering studies and physics at high school two years in a row. When deciding on tertiary study, she took a practical view and chose to do what she was good at.
A varied career
It is only 16 years since Veronica Gray commenced her studies at the University of Newcastle (UON), graduating in 2008 with a Bachelor of Science (Physics) and a Bachelor of Engineering (Mechanical) Honours.
During this time, she worked as a ship’s engineer, and with Pivot Maritime International conducted research on simulating rogue wave and shallow water effects on commercial maritime vessels and infrastructure.
After graduating, Gray joined the Defence Science and Technology Organisation as a joint systems scientist, focusing on future warfare in the electromagnetic spectrum, asymmetrical warfare and systems engineering and architecture.
She returned to UON in 2010 to undertake a PhD on single crystal properties of MAX phase ceramics using inelastic neutron scattering, conducting experiments at the Los Alamos National Lab in the US and ANSTO in Australia.
Following this, she took up an industry research position with Rolls Royce at Swansea University in Wales. Gray spent four years there, investigating aerospace and power generation materials, focusing on creep and fatigue, dynamic testing as well as ultra-high temperature testing.
She returned to Australia in 2018 and took up her current role with QUT, where she lectures in mechanical engineering and works on the frontier of materials research.