New method opens the way for cutting tools with longer lifetime

March 8, 2019, Linköping University
Kostas Sarakinos, Davide Sangiovanni and Georgio Almyras. Credit: Anna Nilsen

Researchers at Linköping University, LiU, have developed a theoretical model that enables simulations for showing what happens in hard cutting materials as they degrade. The model will enable manufacturing industries to save time and money. The model has been published in the open access scientific journal Materials.

Titanium-aluminium nitride is a commonly used as a coating for metal cutting tools. With the aid of a titanium-aluminium nitride thin film, the cutting edge of a coated tool becomes harder, and the lifetime of the tool longer. A notable feature of the coated surface is that it becomes even harder during the cutting process, a phenomenon that is known as age hardening.

Kostas Sarakinos, associate professor in at Linköping University, describes the material as a workhorse in manufacturing industry.

The alloy is, however, sensitive to high temperature. A few minutes of cutting operation in a truly hard material subjects the cutting edge to such a high pressure that it is heated to nearly 900 degrees or above. At temperatures up to 700 degrees, the material is unharmed, but it starts to degrade at higher temperatures. The edge softens and loses sharpness.

Until now, no one has been able to determine what happens at the atomic level inside the thin film during the cutting process. It has only been possible to partially simulate the properties of the complex combination of titanium, aluminium and nitrogen, and it has not been possible to draw any conclusions from the results.

Georgios Almyras, who previously worked as a post-doctoral researcher at the Nanoscale Engineering Division and has now moved to Ericsson, Davide Sangiovanni of the Division of Theoretical Physics, and Kostas Sarakinos, head of the Nanoscale Engineering Division, Linkoping University, spent four years developing a reliable theoretical that can be used to show exactly what happens in the material with picosecond time resolution. They have used the newly developed model to simulate events in the material, showing which atoms are displaced and the consequences this has for the properties.

"This also means that we can develop strategies to stop the degradation, such as alloying the materials or creating specially-designed nanostructures," says Davide Sangiovanni.

Their theoretical model calculates the forces between the atoms in the material. The model is based on a previously known method that has been successfully used in simple material systems. Complex combinations of materials, however, require time-demanding calculations that are only possible in a supercomputer. The research group from LiU has optimized these calculations by implementing machine learning algorithms which the predecessors of artificial intelligence.

The supercomputer at the National Supercomputer Centre at LiU has then been used for calculations of around 40 alloys of the three elements titanium, aluminium and nitrogen, while looking at several properties of the material. The scientists have then compared the results from the calculations with the known properties of the .

"The agreement is very good," says Kostas Sarakinos. "It's important that we have calculated also properties that we know, because then we can be sure that the calculations and predictions of the model are reliable."

The researchers hope that the method will be useful for companies in the manufacturing industry, such as Sandvik, ABB, Seco Tools, etc., which could save a lot of money by developing tools with greater hardness and resistance to wear. These are companies with which the LiU researchers have long-term collaboration agreements.

"We can now for the first time carry out large-scale classical simulations of atomic structures in one of the material systems most commonly used for metal cutting and forming. The simulations can consider resistance to heat or nanostructures, and they may provide important insight into how the atoms move. The results will help us avoid, or at least delay, degradation of the material," says Kostas Sarakinos.

Explore further: Revealing the inner working of magnetic materials

More information: G. Almyras et al. Semi-Empirical Force-Field Model for the Ti1−xAlxN (0 ≤ x ≤ 1) System, Materials (2019). DOI: 10.3390/ma12020215

Related Stories

Revealing the inner working of magnetic materials

November 8, 2018

Björn Alling, researcher in theoretical physics at Linköping University, has, together with his colleagues, completed the task given to him by the Swedish Research Council in the autumn of 2014: Find out what happens inside ...

Theories describe dynamically disordered solid materials

February 11, 2019

Theoretical physicists at Linköping University have developed a computational method to calculate the transition from one phase to another in dynamically disordered solid materials. This is a class of materials that can ...

Supercomputing helps study two-dimensional materials

February 4, 2019

Materials scientists study and understand the physics of interacting atoms in solids to find ways to improve materials we use in every aspect of daily life. The frontier of this research lies not in trial and error, though; ...

Elusive atomic motion captured by electron microscopy

May 9, 2017

The movement of atoms through a material can cause problems under certain circumstances. Atomic-resolution electron microscopy has enabled researchers at Linköping University in Sweden to observe for the first time a phenomenon ...

Recommended for you

Coffee-based colloids for direct solar absorption

March 22, 2019

Solar energy is one of the most promising resources to help reduce fossil fuel consumption and mitigate greenhouse gas emissions to power a sustainable future. Devices presently in use to convert solar energy into thermal ...

EPA adviser is promoting harmful ideas, scientists say

March 22, 2019

The Trump administration's reliance on industry-funded environmental specialists is again coming under fire, this time by researchers who say that Louis Anthony "Tony" Cox Jr., who leads a key Environmental Protection Agency ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.