The requirements for steels applied in the automotive industry are manifold: strong steels are used for centre pillars, the part of a car installed next to the driver’s door. On the other hand, the front part of a car must consist of strong and at the same time ductile material.
Thus, in case of a crash, the shock energy can be absorbed and the driver is protected. Dr. Dirk Ponge, group leader at the MPIE, has achieved to combine both requirements in one class of new steel, named “lean maraging TRIP steels”. Due to a high nickel content conventional maraging steels are very strong and used in air plane landing gear. The term maraging merges ‘martensite’ and ‘aging’.
The name is derived from a special heat treatment (aging) which strengthens an already quite strong martensite structure. ”The use of a high amount of nickel results in a strong steel, but also caused an expensive production.” That’s why Ponge reduced the nickel content and found a surprising effect.
Combination of strength and ductility
During heat treatment, the formation of intermetallic precipitations causes an increase in strength. At the same time austenite is formed which is the reason for the increase in ductility and the basis for a second effect: the TRIP effect. TRIP stands for transformation induced plasticity. Triggered by a deformation process, a phase transformation from metastable austenite to martensite takes place in the material. This leads to an increase in strain hardening rate and enables to reach high elongations. With both these effects occurring, one obtains a good combination of tensile strength and total elongation up to 30.000 MPa%. The intermetallic precipitations, which are responsible for the excellent properties are analysed with the 3-dimensional atom probe.
Optimisation by computational materials design
Currently, the development of these steels is being optimised. Ponge expects to further decrease the production costs and to improve the mechanical properties by modifying the alloy composition. This is performed in close cooperation with the department of Computational Materials Design. The department of Prof. Jörg Neugebauer is calculating with the means of quantum physics, which precipitations are formed in the material with respect to the composition. This improves the efficiency of the further development and reduces the number of experiments. A systematic and application-oriented development of the lean high-performance steels is on the way.
Yasmin A. Salem, M.A.
Max-Planck-Institut für Eisenforschung GmbH
phone: +49 (0)211 6792 722
fax: +49 (0)211 6792 218
Yasmin A. Salem | Source: MPIE
Further information: www.mpie.de
More articles from Automotive Engineering:
Los Alamos catalyst could jumpstart e-cars, green energy
05.06.2013 | DOE/Los Alamos National Laboratory
New Speaker System for Cars Creates Separate “Audio Zones” for Front and Rear Seats
03.06.2013 | Acoustical Society of America (ASA)
- Biological fermentation process converts CO and CO2 into bioethanol and platform chemicals
- Process uses energy contained in steel plant off-gases
- Ten-year co-operation to develop and market integrated environmental solutions for the steel industry worldwide
Siemens Metals Technologies and LanzaTech have signed a ten-year co-operation agreement to develop and market integrated environmental solutions for the steel industry worldwide. The collaboration will utilize the ground-breaking fermentation technology developed by LanzaTech transforming carbon-rich off-gases generated by the steel industry into low carbon bioethanol and other platform chemicals. ...
Novel application of 3D printing could enable the development of miniaturized medical implants, compact electronics, tiny robots, and more
3D printing can now be used to print lithium-ion microbatteries the size of a grain of sand. The printed microbatteries could supply electricity to tiny devices in fields from medicine to communications, including many that have lingered on lab benches for lack of a battery small enough to fit the ...
... two engines aircraft project “Elektro E6”.
The countdown has been started for opening the gates again for the worldwide leading aviation and space event in Le Bourget, Paris from June 17th - 23rd, 2013.
EADCO & PC-Aero will present at the Paris Air Show in Hall H4 booth F-7 their new future aircraft and innovative project: ...
Siemens scientists have developed new kinds of ceramics in which they can embed transformers.
The new development allows power supply transformers to be reduced to one fifth of their current size so that the normally separate switched-mode power supply units of light-emitting diodes can be integrated into the module's heat sink.
The new technology was developed in cooperation with industrial and research partners who ...
Cheaper clean-energy technologies could be made possible thanks to a new discovery.
Led by Raymond Schaak, a professor of chemistry at Penn State University, research team members have found that an important chemical reaction that generates hydrogen from water is effectively triggered -- or catalyzed -- by a nanoparticle composed of nickel and phosphorus, two inexpensive elements that are abundant on Earth. ...
19.06.2013 | Life Sciences
19.06.2013 | Agricultural and Forestry Science
19.06.2013 | Studies and Analyses
14.06.2013 | Event News
13.06.2013 | Event News
10.06.2013 | Event News