British researchers found crucial clues to improve the performance of a new class of advanced alloys. This game-changing achievement might guide us to a milestone of the long search for reliable structural materials operating at elevated temperatures. The success of this campaign will help solve challenges for high-temperature materials. Those novel alloys will eventually make a variety of exciting technologies feasible, including high-efficiency jet engines, next-generation nuclear reactors, and controlled fusion facilities,
Materials inevitably become soft as temperature rises. Researchers have been using ultra-fine inclusions with exceptional hardness to enhance the strength of steels, namely, making “nanoscale concrete”, for applications above 700°C. This class of steels are therefore called oxide dispersion-strengthened (ODS) steels. However, aluminum, an essential addition to relieve high-temperature corrosion, prevents the formation of the ultra-fine inclusions by constituting large-sized aluminum-containing particles. Hence, researchers had to face a compromise between corrosion resistance and mechanical properties when developing ODS steels.
Dr. Dawson and his team aimed to change this embarrassing situation. Those scientists from University of Liverpool and University of Manchester tried to reduce the particle size in a powder-form legacy commercial aluminum-containing ODS steel, PM2000, by carefully controlling the heat treatment conditions. After that, they measured the size, number density and orientation of the formed particles by means of various advanced microstructure characterization techniques.
The results are splendid. The researchers managed to obtain aluminum-containing ODS steel powder including dispersed and dense distribution of ultra-fine particles. In fact, the particles in Dr. Dawson’s powder are as fine as those particles in aluminum-free ODS steels. The powder can then be consolidated into bulk steel.
The success of making this excellent aluminum-containing ODS steel powder affirmatively expanded our understanding of ODS alloys. This knowledge is indispensable for the development of practical high-temperature structural materials. Once those materials are ready for practical applications, human beings will eventually have solutions to the material challenges raised by the extreme environment brought by those revolutionary conceptions such as fusion reactions.
For further information Read the Journal of Nuclear Materials original research article which this summary is based on Nano-particle precipitation in mechanically alloyed and annealed precursor powders of legacy PM2000 ODS alloy (September 2015).
Visit the profile of the research ambassador, Yinbin Miao, who wrote this summary.
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