Super strong alloy discovered
Image: The University of Sydney
University of Sydney researchers have discovered a new super-strength light alloy and had their key findings published in the prestigious journal, Nature Communications.
The
alloy is much stronger than expected and the reasons are being revealed
by top-end microscopy and microanalysis at the University’s node of the
Australian Microscopy and Microanalysis Research Facility (AMMRF).
Dr Peter Liddicoat and Professor Simon Ringer from the Australian Centre for Microscopy and Microanalysis (ACMM) and Dr Xiaozhou Liao from the University of Sydney’s School of Aerospace, Mechanical and Mechatronic Engineering, have headed up this international collaborative project.
The
purpose of their research has been to understand the relationship
between the alloy’s properties and its structure at the atomic level.
The
importance of developing new lightweight alloys cannot be overestimated
and will enable improved technologies, particularly in aerospace and
automotive applications and in construction.
The alloy produced by Dr Liddicoat and the rest of the team is much stronger than previous crystalline metals.
It
has high strength and good ductility, a highly sought-after
combination, and the physical improvements observed were significantly
beyond what was predicted by standard rules.
To understand this
improvement, Dr Liddicoat characterised the nanostructure of the alloy
by using atom probe tomography at the ACMM, allowing the structure of
the grains and tiny clusters of solute atoms to be visualised. The
grains were just tens of nanometres in diameter with accumulations of
solute atoms apparent along the boundaries between the grains.
The
unexpectedly high level of strengthening appears to be due to two
factors. Firstly, the way that the alloying elements are arranged within
the grains is thought to increase the dislocation-storage capacity of
the alloy. Secondly, the clustering of elements between the grains could
limit nanocrystal growth, increase the cohesion of the grains, and
resist embrittlement and defect generation.
Dr Liddicoat is very enthusiastic about understanding alloys in this way.
“Being
able to really see what is happening inside our alloys at the atomic
level has been a huge help in investigating their amazing properties,”
he said.
“An exciting aspect of the study was our development of
breakthrough new atom probe methods to measure the orientation of
nanometre-sized crystals to assess ‘nanotexture’.”
