Transformation toughening of ceramics made crystal clear
University of Tsukuba researchers use a time-resolved X-ray crystallography method to gain a better understanding of phase changes in zirconia ceramics
2021-06-09
(Press-News.org) Tsukuba, Japan - Ceramic materials that are resistant to cracking are used in a variety of industries from aerospace engineering to dentistry. Toughening them to improve their efficiency and safety is therefore an important area of investigation. Researchers from the University of Tsukuba have used time-resolved X-ray diffraction to observe transformation toughening in zirconia ceramics during dynamic fracture. Their findings are published in Applied Physics Letters.
Current methods of observation allow the formation of cracks in materials to be observed in situ while loads are applied. These close-up analyses can capture changes on a very small scale with fast resolution, providing clear pictures of fractures and of how the material resists them through toughening.
However, transformation toughening of ceramic materials is related to changes in their arrangement on the atomic level, which can't be seen using the available techniques. Getting a real-time picture of such transformations in the crystal structure is important for gaining a complete picture of how materials respond to dynamic loading.
The researchers therefore used time-resolved X-ray diffraction to follow the behavior of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) subjected to shock loading.
"Y-TZP is a widely used ceramic material with high strength and fracture toughness that has numerous applications. There is therefore a lot of focus on understanding it better so that we can continue to optimize it," explains Professor Atsushi Kyono. "Until now, we haven't had a clear picture of when in the fracture process crystal structure changes take place, so our understanding of transformation toughening in Y-TZP has been slightly muddy."
Under normal conditions, Y-TZP has a tetragonal crystal structure. This didn't change when the load was applied. However, when dynamic fracture started, small amounts of the monoclinic phase were detected. This indicated that dynamic fracture contributes to the transformation toughening process.
The researchers showed that transformation toughening is related to a process known as spall fracture, which provides insight into the origin of the high spall strength of zirconia ceramics.
"In addition to revealing some of the underlying causes for the behavior of zirconia ceramics, we have demonstrated the feasibility of our method for in situ analysis of crystal structure changes," says study first author Sota Takagi. "We believe that our findings will contribute to the continued development of tough ceramics for a wide range of applications from electric insulator parts to kitchen utensils."
INFORMATION:
The article, "Visualization of transformation toughening of zirconia ceramics during dynamic fracture", was published in Applied Physics Letters at DOI: https://doi.org/10.1063/5.0044607.
ELSE PRESS RELEASES FROM THIS DATE:
2021-06-09
Human cells are kept healthy by the activity of millions of proteins. These proteins are modified in different ways, such as by adding sugar molecules to them, which can be crucial for them to function properly. Given this importance, defects in the sugar-adding process are often lethal at the very early stages of development. In rare cases, however, patients can develop sugar-adding deficiencies that result in a range of metabolic diseases, known collectively as 'congenital disorders of glycosylation' (CDG). These disorders are caused by defects in the enzymes involved in the sugar-adding process. For example, ALG2-CDG (or CDG-Ii) is a disorder caused by mutations in the ALG2 enzyme, ...
2021-06-09
MELVILLE, N.Y., June 9, 2021 -- Designing a soundscape to improve the quality of life for an individual is centered on putting their perception at the heart of the process. It becomes trickier for people who have diminished cognitive capacities.
During the 180th Meeting of the Acoustical Society of America, which will be held virtually June 8-10, Arezoo Talebzadeh, from Ghent University, will show how a personalized soundscape can help those with dementia by providing clues regarding time of day and place. The session, "Soundscape design for people with dementia; the correlation between psychoacoustic parameter and human perception," will take place Wednesday, June 9, ...
2021-06-09
UPTON, NY--How do you spot a subatomic neutrino in a "haystack" of particles streaming from space? That's the daunting prospect facing physicists studying neutrinos with detectors near Earth's surface. With little to no shielding in such non-subterranean locations, surface-based neutrino detectors, usually searching for neutrinos produced by particle accelerators, are bombarded by cosmic rays--relentless showers of subatomic and nuclear particles produced in Earth's atmosphere by interactions with particles streaming from more-distant cosmic locations. These abundant travelers, mostly muons, create a web of crisscrossing particle tracks that can easily obscure a ...
2021-06-09
Fruits, vegetables, red wine and chocolate are all rich in polyphenols, natural plant compounds that double as cancer-fighting antioxidants. We can access these foods' health benefits because the microbes in our guts happily feast on them, breaking them down into smaller chemical components.
Microbiome scientists at Colorado State University wanted to know if microbes can also break down those same polyphenols in systems outside the human body, including the microbial wild west of soils.
A research team led by Kelly Wrighton, associate professor in the College of Agricultural Sciences' Department of Soil and Crop Sciences, has uncovered new insights into the role of polyphenols in the soil microbiome, known as a black box for its complexity. They proffer an updated theory that soils ...
2021-06-09
Los Angeles (June 8, 2021) --
IBDs, including Crohn's disease and ulcerative colitis, are chronic conditions that occur when the intestinal immune system becomes overreactive, causing chronic diarrhea and other digestive symptoms. In a published survey at the beginning of COVID-19 vaccine distribution, 70% of IBD patients reported concern about side effects from the vaccines.
"What we've learned is that if you have IBD, the side effects you're likely to experience after a vaccine are no different than they would be for anyone else," said Gil Melmed, MD, corresponding author of the study and director of Inflammatory Bowel Disease Clinical Research at Cedars-Sinai. "If ...
2021-06-09
Real-world data from Sleep Number® smart bed sleepers shows a potential model for predicting and tracking COVID-19 infection using sleep and biometric measures.
Analysis of 18.2 million 360 smart bed sleep sessions finds heart rate variability differs with age, gender and day of the week.
MINNEAPOLIS, MN -- June 9, 2021 -- Today, END ...
2021-06-09
Deaths from suicide are rising in the United States. These rising trends are especially alarming because global trends in suicide are on a downward trajectory. Moreover, in the U.S., the major mode of suicide among young Americans is by firearms.
Researchers from Florida Atlantic University's Schmidt College of Medicine and collaborators explored trends in suicide by firearms in young white and black Americans (ages 5 to 24 years) from 1999 to 2018. Results, published in the journal Annals of Public Health and Research, showed that between 2008 and 2018, rates of suicide by firearms quadrupled in young Americans ages 5 to 14 ...
2021-06-09
Chemical rings of carbon and hydrogen atoms curve to form relatively stable structures capable of conducting electricity and more -- but how do these curved systems change when new components are introduced? Researchers based in Japan found that, with just a few sub-atomic additions, the properties can pivot to vary system states and behaviors, as demonstrated through a new synthesized chemical compound.
The results were published on April 26 in the Journal of the American Chemical Society.
"In the past decade, open-shell molecules have attracted considerable attention not only in the field of reactive intermediates, but also in materials science," said paper author Manabu Abe, ...
2021-06-09
In the first three quarters of 2020, the COVID-19 pandemic caused a 30% fall in electronic and electrical equipment sales in low- and middle-income countries but only a 5% decline in high-income countries, highlighting and intensifying the digital divide between north and south, according to a new UN report.
Worldwide, sales of heavy electric appliances like refrigerators, washing machines and ovens fell the hardest -- 6-8% -- while small IT and telecommunications equipment decreased by only 1.4%. Within the latter category, sales of laptops, cell phones and gaming equipment rose in high-income countries and on a global basis, but fell in low- and middle-income ...
2021-06-09
To focus on what's new, we disregard what's not. A new study by researchers at MIT's Picower Institute for Learning and Memory substantially advances understanding of how a mammalian brain enables this "visual recognition memory."
Dismissing the things in a scene that have proven to be of no consequence is an essential function because it allows animals and people to quickly recognize the new things that need to be assessed, said Mark Bear, Picower Professor in the Department of Brain and Cognitive Sciences and senior author of the study in the Journal of Neuroscience.
"Everyone's appropriate behavioral response to an unexpected stimulus is to devote attentional resources to that," Bear said. "Maybe it means danger. Maybe it means food. But if you learn that this once-novel ...
LAST 30 PRESS RELEASES:
[Press-News.org] Transformation toughening of ceramics made crystal clear
University of Tsukuba researchers use a time-resolved X-ray crystallography method to gain a better understanding of phase changes in zirconia ceramics
