قالب وردپرس درنا توس
Home https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Science https://server7.kproxy.com/servlet/redirect.srv/sruj/smyrwpoii/p2/ Cracking the mystery of nature's most difficult material

Cracking the mystery of nature's most difficult material



<div data-thumb = "https://scx1.b-cdn.net/csz/news/tmb/2019/crackingthem.jpg" data-src = "https://scx2.b-cdn.net /gfx/news/hires/2019/crackingthem.jpg "data-sub-html =" Highly deformed and restored pearl. Scheme of the inner surface of the shell of the bivalve mollusc P. nobilis, with the area examined being marked with a purple square b outline HAADF STEM Cross-sectional Tablets for Tablets Before Compression cc STEM High-Resolution Image of Two Tablets and Their Organic Interfaces Before Compression dd Tablets Closely Closed at a Compressive Load of 40 µN e. After the indenter has been downloaded, the tablets and the organic interface have completely restored their original morphology, the insertions show the movement of the organic inclusions due to the deformation of the tablet and their full restoration after removal of the pressure load Credit: Nature Communications (201
9). DOI: 10.1038 / s41467-019-12743-Z ">

<img src = "https://scx1.b-cdn.net/csz/news/800/2019/crackingthem.jpg" alt = "Breaking the mystery of nature's most difficult material" title = "Strong deformed and reconstructed perforation – scheme of the inner surface of the shell of the bivalve mollusc P. nobilis, the study area being marked with a purple square b HAADF STEM overview image of a cross-sectional interface of tablets with curtains before compression c high resolution STEM image the ability of two tablets and their organic interface before compression d Tablets tightly closed when pressed at 40 µN compression load e. After the indenter has been withdrawn, the tablets and the organic interface have completely restored their original morphology, the insertions show the movement of the organic inclusions due to the deformation of the tablet and their full restoration after removal of the pressure load Credit: Communications (2019). DOI: 10.1038 / s41467-019-12743-z "/>
Strongly deformed and restored percussion. Scheme of the inner surface of the shell of bivalve mollusc P. nobilis, the study area being marked with a purple square. b HAADF STEM overview of the cross-sectional interface of the feather tablets before being compressed. c High-resolution STEM image of two tablets and their organic interface before compression. d Tablets tightly closed at 40 compression load. e After the indenter has been downloaded, the tablets and the organic interface completely restore their original morphology. The insets show the movement of the organic inclusions due to the deformation of the tablet and their full restoration after removal of the compression load. Credit: Natural Communications (2019). DOI: 10.1038 / s41467-019-12743-z

The arc-lined core, which delineates the insides of mussels and other molluscs, is known as nature's most difficult material. Now a team of researchers led by the University of Michigan has revealed in real time exactly how it works.


Better known as mother-of-pearl, the combination of pearl hardness and resistance has been mystifying scientists for more than 80 years. If people could imitate it, it could lead to a new generation of super-strong synthetic materials for structures, surgical implants and countless other applications.

"We humans can make more difficult materials using an unnatural environment, such as extreme heat and pressure. But we cannot reproduce the kind of nanotechnology that molluscs have achieved. Combining the two approaches can lead to a grand new generation of materials, and this document is a step in that direction, "says Robert Howden, UM Assistant in Materials Science and Engineering.

Researchers have known the basics of the secret of curtains for decades – it was made by microscopic "bricks" of a mineral called aragonite, lined with "mortar" made of organic material, this arrangement of bricks and mortar apparently gives it strength, but the curtain is far stronger than its materials suggest. [19659004] The Hovden team, which includes assistant research assistant for JM materials Jiseok Gim, as well as geochemists at the Australian University of Macquarie and elsewhere, worked together

At the Michigan Center for Material Characterization in Michigan, researchers used small piezoelectric micro-indents to exert force on the shells of Pinna nobilis, commonly known as the noble shell of the pen, while under electron microscope. They watched what happened in real time.

They discovered that "bricks" are actually multilateral tablets of only a few hundred nanometers in size. Typically, these tablets remain separate, stacked and thin with an organic mortar layer. But when stress is applied to the shells, the "mortar" slides away and the tablets lock together, forming what is essentially a solid surface. When the force is removed, the structure springs back without losing force or resistance.

This durability separates curtains from even the most modern materials created by man. Plastics, for example, can come back from impact, but they lose some of their power every time. Dacre does not lose its resistance to repeated blows up to 80% of the yield force

Moreover, if a crack is formed, the pearl limits the crack to one layer, but does not allow it to spread, keeping the structure of the shell intact.

"It's amazing that a mollusk, which is not the most intelligent creature, creates so many structures in so many rocks," Hovden said. "It's the production of individual calcium carbonate molecules, arranging them in nanosheets that are glued together with organic material, right down to the shell structure, which combines a pearl with several other materials."

Howden believes that humans could use mussel methods to create nano-created composite surfaces that could be dramatically lighter and healthier than those available today.

"Nature provides us with these highly optimized structures with millions of years of evolution behind them," he said. "We could never run enough computer simulations to invent these – they are just there to find them."

The study was published in by Nature Communications .


The materials teach how the pearl is made


More information:
Jiseok Gim et al., Nanoscale deformation mechanics reveals resistance in the curtain of Pinna nobilis shell Nature Communications (2019). DOI: 10.1038 / s41467-019-12743-z

Provided by
University of Michigan
Reference :
Breaking down the mystery of nature's most difficult material (2019, October 23)
retrieved 23 October 2019
from https://phys.org/news/2019-10-mystery-nature-toughest-material.html

This document is copyright. Apart from any fair dealing for private or research purposes, no
part may be reproduced without written permission. Content is provided for information only.


Source link