Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Metallic glass: cracking the mystery of flaws


An interdisciplinary study exposes how structural flaws dictate failure strength and deformation in nanosized alloys with super-resilient properties.

A study from A*STAR reveals that designers of metallic-glass-based nanodevices must account for tiny flaws in alloy frameworks to avoid unpredictable catastrophic failure[1]. Understanding how nanoscale metallic glass fractures and fails when subjected to external stress is critical to improving its reliability in devices and composites.

Experimental measurements (left and right) and molecular dynamics simulations (middle) of metallic glass nanopillars reveal that structural flaws play important roles in determining material strength.

Copyright : Adapted by A*STAR with permission from Ref. 1. Copyright 2014 American Chemical Society.

Recently, researchers have found evidence that artificial flaws — miniscule notches carved into the alloy — do not affect the material’s overall tensile strength. But other work has shown that such notches may actually induce the formation of localized cracks.

Mehdi Jafary-Zadeh and co-workers from the A*STAR Institute of High Performance Computing, in collaboration with researchers in the United States, used a combination of physical experiments and computational simulations to study nanoscale flaw tolerance with in-depth precision.

First, the researchers fabricated nickel–phosphorous metallic glass into narrow ‘nanopillars’ bearing tiny notches and mushroom-shaped endcaps that served as tension grips (see image). Guided by high-resolution scanning electron microscopy, they systematically pulled the structures apart until they cracked — an action that consistently occurred at the notched zone, and at failure strengths 40 per cent lower than those for unflawed nanopillars.

The team then turned to massive molecular dynamics simulations to explain these physical results. “Simulating failure modes in the nanopillar metallic glasses required large-scale, three-dimensional models containing millions of atoms,” says Jafary-Zadeh. “Performing simulations at these scales is pretty daunting, but we overcame this challenge with the help of the A*STAR Computational Resource Centre.”

When the researchers modeled atomic strain during nanopillar elongation, they found that the un-notched structures failed via a plastic type of deformation known as shear banding. However, the notched structures were brittle and failed through crack propagation from the flaw point at tensile strengths significantly smaller than the un-notched samples (see video). These observations suggest that ‘flaw insensitivity’ may not be a general feature of nanoscale mechanical systems.

“The theory of flaw insensitivity postulates that the strength of materials that are intrinsically brittle or have limited plastic deformation modes approaches a theoretical limit at the nanoscale, and does not diminish due to structural flaws,” explains Jafary-Zadeh. “However, our results show that failure strength and deformation in amorphous nanosolids depend critically on the presence of flaws.”

Jafary-Zadeh notes that the excellent agreement between experimental results and the simulations is exciting and demonstrates how such computations can bridge the knowledge gap between macroscopic mechanical fracturing and the hidden corresponding mechanisms taking place at atomistic time and length scales.

The A*STAR-affiliated researchers contributing to this research are from the Institute of High Performance Computing.


1. Gu, X. W, Jafary-Zadeh, M., Chen, D. Z., Wu, Z., Zhang, Y.-W. et al. Mechanisms of failure in nanoscale metallic glass. Nano Letters 14, 5858–5864 (2014).

Associated links

A*STAR Research | ResearchSEA
Further information:

More articles from Interdisciplinary Research:

nachricht Tiny implants for cells are functional in vivo
19.03.2018 | Universität Basel

nachricht Scientists develop new tool for imprinting biochips
09.03.2018 | Advanced Science Research Center, GC/CUNY

All articles from Interdisciplinary Research >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Space observation with radar to secure Germany's space infrastructure

Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.

The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

New solar solutions for sustainable buildings and cities

23.03.2018 | Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

Latest News

Don't Give the Slightest Chance to Toxic Elements in Medicinal Products

23.03.2018 | Life Sciences

Sensitive grip

23.03.2018 | Materials Sciences

No compromises: Combining the benefits of 3D printing and casting

23.03.2018 | Process Engineering

Science & Research
Overview of more VideoLinks >>>