Layered material displays strength of ceramic with toughness of metal

Good news! This could be a major breakthrough!

My next coffee mug will never break again! Just kidding!

"Lattice-matching prevents brittleness usually associated with ceramics"

"A new technique allows ceramics to become more ductile without losing their strength. It involves the controlled growth of a metal layer on the ceramic surface, which allows its structure to rearrange under stress rather than failing. The researchers behind the work suggest that the method could allow ceramics to be used in biomedical and aerospace applications for which they are currently ill-suited. ...

In the new work, Chen and her colleagues combined the properties of ceramics and metals by literally combining the two materials. The researchers used mixed aqueous precursors of lanthanum oxide and molybdenum in solution before drying and sintering the resulting gel. The material comprised strongly bonded, lattice-matched layers of metal and ceramic. ..."

From the editor's summary and abstract:

"Editor’s summary

Ceramics break instead of deforming plastically, which can be partially attributed to their low number of dislocation defects compared with more ductile materials such as metals. Dong et al. show that by carefully choosing a ceramic-metal interface, the dislocation defects generated in the metal during straining can migrate into the ceramic. The result is a dramatic improvement in the tensile properties, suggesting a different way to improve the properties of brittle ceramics. ...

Abstract

The inherent brittleness of ceramics, primarily due to restricted atomic motions from rigid ionic or covalent bonded structures, is a persistent challenge. This characteristic hinders dislocation nucleation in ceramics, thereby impeding the enhancement of plasticity through a dislocation-engineering strategy commonly used in metals. Finding a strategy that continuously generates dislocations within ceramics may enhance plasticity. Here, we propose a “borrowing-dislocations” strategy that uses a tailored interfacial structure with well-ordered bonds. Such an approach enables ceramics to have greatly improved tensile ductility by mobilizing a considerable number of dislocations in ceramic borrowed from metal through the interface, thereby overcoming the challenge associated with direct dislocation nucleation within ceramics. This strategy provides a way to enhance tensile ductility in ceramics."

P.S. I hate when science journals systematically reduce the first names of researchers to their initials!!!! Bad practice!!!!

Science is published by Marxist ideologues of AAAS! I believe, this is also ideologically driven. This article's last author is a female, Kexin Chen (Tsinghua University)! Google Scholar does not even have a profile on her (see screen print below)!!!!

The publisher of her book (Elsevier) does not have a profile on her either!!!!

Layered material displays strength of ceramic with toughness of metal | Research | Chemistry World

Borrowed dislocations for ductility in ceramics (no public access)

Chen’s team report that the glide of partial dislocations in the layered structure relieves stress in the material

Researcher Kexin Chen presumably published also this book

Pottery reshapes understanding of Australia's First Nations people

Prehistoric life on the Great Barrier Reef!

"... The archaeologists say this significant finding challenges notions that Aboriginal Australian communities were unaware of pottery manufacture before European settlement: “…instead suggesting a rich history of long-distance cultural exchanges and technological innovation long before British arrival.” ..."

From the abstract:

"Aboriginal manufacture and use of pottery was unknown in Australia prior to European settlement, despite well-known ceramic-making traditions in southern Papua New Guinea, eastern Indonesia, and the western Pacific. The absence of ancient pottery manufacture in mainland Australia has long puzzled researchers given other documented deep time Aboriginal exchange networks across the continent and the close proximity of pottery-bearing Lapita and post-Lapita maritime communities in the western Pacific with ocean-going watercraft and sophisticated navigation abilities. We report the oldest securely dated ceramics found in Australia from archaeological excavations on Jiigurru (Lizard Island Group) on the Great Barrier Reef, northeast Australia. Comprehensive radiocarbon dating and Bayesian modelling constrains ceramic deposition to between 2950–2545 cal BP and 1970–1815 cal BP. This timing overlaps with late Lapita and post-Lapita ceramic traditions of southern Papua New Guinea. Geological characterisation of the sherds strongly suggests local manufacture as the vessels belong to three temper and clay groups locally sourced to northeast Australia, and most likely to Jiigurru. The oldest occupation layers date to 6510–5790 cal BP, making Jiigurru the earliest offshore island occupied on the northern Great Barrier Reef. The results demonstrate that northeast Australian First Nations communities had sophisticated canoe voyaging technology and open-sea navigational skills and were intimately engaged in ancient maritime networks, connecting them with peoples, knowledges, and technologies across the Coral Sea region."

Pottery reshapes understanding of First Nations people What’s believed to be the first evidence of pottery making by Australia’s First Nations people has been unearthed in far north Queensland.

Early Aboriginal pottery production and offshore island occupation on Jiigurru (Lizard Island group), Great Barrier Reef, Australia (open access)

Fig. 1. Top: Map of known Lapita cultural area showing the location of Jiigurru (Lizard Island Group) ... Dashed extension of the Lapita cultural area into Torres Strait and northeast Australia indicates possible Lapita distribution or influence ...  Bottom: Median onset ages for pre-nineteenth century ceramic sites in the Coral Sea region. Median calibrated ages have been rounded to nearest 50 years. Only sites with published radiocarbon chronologies are included ...

Fig. 2. Visualisation of sea-level rise on Jiigurru (Lizard Island Group) since the Last Glacial Maximum. By at least −30 m (10,000 years ago), Jiigurru would have been surrounded by water.

Fig. 11. Ceramic sherd selection.

Engineers develop a new kind of shape-memory material

Amazing stuff!

"Shape-memory metals, which can revert from one shape to a different one simply by being warmed or otherwise triggered, have been useful in a variety of applications, as actuators that can control the movement of various devices. Now, the discovery of a new category of shape-memory materials made of ceramic rather than of metal could open up a new range of applications, especially for high-temperature settings, such as actuators inside a jet engine or a deep borehole. ...
Now, the MIT team has found a way to overcome that and produce a ceramic material that can actuate without accumulating damage, thus making it possible for it to function reliably as a shape-memory material through many cycles of use. ...
The hysteresis changed so dramatically that it now resembles that of metals ..."

From the abstract:

"Zirconia ceramics exhibit a martensitic phase transformation that enables large strains of order 10%, making them prospects for shape-memory and superelastic applications at high temperature. Similarly to other martensitic materials, this transformation strain can be engineered by carefully alloying to produce a more commensurate transformation with reduced hysteresis (difference in transformation temperature on heating and cooling). However, such ‘lattice engineering’ in zirconia is complicated by additional physical constraints: there is a secondary need to manage a large transformation volume change, and to achieve transformation temperatures high enough to avoid kinetic barriers. Here we present a method of augmenting the lattice engineering approach to martensite design to address these additional constraints, incorporating modern computational thermodynamics and data science tools to span complex multicomponent spaces for which no data yet exist. The result is a new zirconia composition with record low hysteresis of 15 K, which is about ten times less transformation hysteresis compared to typical values (and approximately five times less than the best values reported so far). This finding demonstrates that zirconia ceramics can exhibit hysteresis values of the order of those of widely deployed shape-memory alloys, paving the way for their use as viable high-temperature shape-memory materials."

Engineers develop a new kind of shape-memory material | MIT News | Massachusetts Institute of Technology The ceramic-based material could be used for highly efficient actuators for aircraft or other uses, with minimal moving parts.

Low-hysteresis shape-memory ceramics designed by multimode modelling (no public access)