Doktorand/Ph.D. student -- mechanical properties
Mechanical properties of powder metallurgical materials
One method to produce metal powder is to disintegrate liquid steel by gas jets of high velocity, often supersonic velocity. The method is called “atomizing” and compared to other methods of producing powder, as water atomizing, or reduction of oxides, it has the advantage that the powder gets high cleanliness, low oxygen content and that the powder particles get spherical shape. This makes gas atomized powder well suited for manufacture of machine parts and tools where high demands are put on mechanical properties. A common application of gas atomized powder is to fill a container of nearly finished shape and use subsequent hot isostatic pressing to form a solid material. An alternative is to press the powder and sinter to finished or near-finished shape. Compared to other production routes, the powder metallurgical way has the advantage of few manufacturing steps, often leading to lower energy consumption, faster production and many times lower total cost. Another advantage with powder metallurgy is that the solidification is very rapid leading to a material free from segregations of alloying elements. This is especially appreciated in high-alloyed materials and it could be mentioned that ASP-steel has considerable finer carbides than conventionally ingot cast high-speed steel, giving ASP-steel considerably better mechanical properties.
The purpose of the PhD project is to gain better understanding for the use of gas atomized powder and its manufacturing process.
The mechanical properties of powder metallurgical and conventional materials (ingot cast, forged and/or rolled) will be studied. The differences are not well known today and are not well reported in literature. The materials that will be studied include austenitic and duplex stainless steel. The impact toughness as well as corrosion and fatigue properties will be tested. The finer microstructure of the gas atomized and HIP-ed material is assumed to have positive effect on these properties but, on the other hand, the PM-materials have generally an increased oxygen level, but also smaller sizes of the oxides inclusions why the effects on the mentioned properties are difficult to predict. There is also need for development of powder testing methods capable of predicting the properties of the finished component. Special interest is given to the coupling between methods of measuring oxygen content and the mechanical and corrosive properties.
Supervision
The graduate student will spend much time at the lab of Erasteel Kloster in Söderfors where there is plenty of equipment for characterising powders and powder metallurgical materials. There are also many skilful researchers and engineers there, working with powder metallurgy as the production of metal powder is located to Söderfors. The academic supervision will be given by Materials Science and Engineering, Royal Institute of Technology, KTH, having a long tradition of research on powder and sintering, both theoretically and experimentally.
Start
During the spring 2012, as agreed upon
Miscellaneous
The employment is for full time and is limited in duration according to “HF 5 kap 7 §”. The research work will be done at HDa Borlänge, KTH Stockholm and at Erasteel Kloster AB, Söderfors.
Information
For further information contact;
Associate professor Annika Borgenstam, Royal Institute of Technology
annika@mse.kth.se, phone 08-790 83 96
Stefan Sundin Erasteel Kloster AB
stefan.sundin@eramet-erasteel.com, phone 0293-54 563
Ansökningshandlingar
Din ansökan med angivet ref nr DUP 2011/739 skall innehålla
- Brev med personlig presentation
- Meritförteckning (CV)
- Styrkta betygshandlingar
- Uppgift om referens
Sista ansökningsdag
Ansökan skall ställas till e-postadress platsansokan@du.se eller postadress Registrator, Högskolan Dalarna, 791 88 FALUN och vara inkommen senast 2011-11-21.
