Development of Ultrafine Grain Structure during Deformation-Thermal Treatment of Austenitic Manganese Steel

Author(s):  
Z. Afshari ◽  
E. Ahmadi ◽  
S. Hossein Nedjad
2012 ◽  
Vol 706-709 ◽  
pp. 1864-1869
Author(s):  
Jozef Zrník ◽  
Libor Kraus ◽  
Stephan Scheriau ◽  
Reinhard Pippan

In this study ultrafine grain structure evolution during high pressure torsion (HPT) of commercial aluminium alloy AA6082 at increased temperature is presented. Two different initial structural states of the alloy were prepared by thermal treatment. The progress in structure refinement in dependence on the shear strain level strain was investigated by TEM of thin foils. The impact of different amount of strain (εef) introduced was analyzed with respect to the effect of increased temperature. The microhardness results measured across the deformed discs pointed out that some data scattering. The results of microstructure analyses showed that ultrafine grain (ufg) structure was already formed in deformed disc upon the first turn, regardless the initial structure of alloy, resulting from prior thermal treatment. The observed heterogeneity in ufg structure formation across the deformed disc was observed, supporting microhardness results scattering. By increasing the strain level (number of turns N-2,4,6), more effectively homogenized ufg structure was observed across the deformed discs. The effect of increased deformation temperature became evident and dynamic recrystalization modified locally ufg structure.. The retardation of new grains growth and higher thermal stability of ufg structure was observed, when two steps thermal treatment of alloy (quenching and ageing) was executed prior deformation. Strength measurements results yielded form tensile tests showed that the effect of structure strengthening was degraded by local recrystallization. The results of torque measurement versus the time showed that the torque required to deform the sample was increasing until the first turn and then kept stable or even decreased.


Alloy Digest ◽  
1976 ◽  
Vol 25 (4) ◽  

Abstract Climax 6Mn-1Mo alloy is a lean austenitic manganese steel which develops a structure similar to that of the well-known Hadfield manganese steel after heat treatment. A lower carbon version of this alloy has been developed to give satisfactory performance in the as-cast condition. Largely because of lower manganese content, these alloys have better abrasion resistance but lower toughness and ductility than Hadfield steel. Both alloys are designed for the many applications where a combination of good wear resistance and moderate toughness is desirable. This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on wear resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: SA-322. Producer or source: Climax Molybdenum Company, A Division of Amax Inc..


2008 ◽  
Vol 584-586 ◽  
pp. 182-187
Author(s):  
Lilia Kurmanaeva ◽  
Yulia Ivanisenko ◽  
J. Markmann ◽  
Ruslan Valiev ◽  
Hans Jorg Fecht

Investigations of mechanical properties of nanocrystalline (nc) materials are still in interest of materials science, because they offer wide application as structural materials thanks to their outstanding mechanical properties. NC materials demonstrate superior hardness and strength as compared with their coarse grained counterparts, but very often they possess a limited ductility or show low uniform elongation due to poor strain hardening ability. Here, we present the results of investigation of the microstructure and mechanical properties of nc Pd and Pd-x%Ag (x=20, 60) alloys. The initially coarse grained Pd-x% Ag samples were processed by high pressure torsion, which resulted in formation of homogenous ultrafine grain structure. The increase of Ag contents led to the decrease of the resulted grain size and change in deformation behavior, because of decreasing of stacking fault energy (SFE). The samples with larger Ag contents demonstrated the higher values of hardness, yield stress and ultimate stress. Remarkably the uniform elongation had also increased with increase of strength.


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