Results found: 3

Number of results on page

Search results

Sort By:

Limit search:

Annealing Effects after Various Thermo-Mechanical Treatments on Microstructure and Mechanical Properties of Wrought Magnesium Alloy ZK60

100%

Oo M., Janeček M., Kral R., Wagner L.

Acta Physica Polonica A

2012

vol. 122

issue 3

606-609

The magnesium alloy ZK60 received from Dead Sea Magnesium in direct-chill cast condition was extruded at T = 350C using an extrusion ratio of ER = 12. The extruded bars were severely plastically deformed at 250C by either equal channel angular pressing or swaging. While swaging led to similar grain refinements as observed after equal channel angular pressing, yield stress and tensile strength values were by far superior in the swaged material. This result is explained by the unfavourable 45° texture component of the (0002) pole figure that develops during the massive shear deformation in equal channel angular pressing. Unlike equal channel angular pressing, the grain orientation after swaging is similar as in the as-extruded condition. Annealing at elevated temperatures indicates very low thermal stability of microstructure and mechanical properties in the equal channel angular pressing material while both properties in the swaged microstructure are as stable as in the as-extruded reference.

Grain Refinement after Various Thermo-Mechanical Treatments in AZ80 and ZK60 Magnesium Alloys

76%

Ryspaev T., Janecek M., Minárik P., Wesling V., Wagner L., Kral R.

Acta Physica Polonica A

2012

vol. 122

issue 3

622-624

The effect of thermal processing prior to severe plastic deformation by extrusion and swaging on grain refinement in ZK60 and AZ80 alloys was studied. The alloys received in direct-chill cast condition were homogenized at 415C and annealed (over-aged) at temperatures from 200 to 380°C. Both the direct-hill cast and over-aged conditions were extruded at T = 300C using an extrusion ratio of ER = 19. Hot extrusion resulted in substantial grain refinement in both cases, the effect being stronger in the over-aged material. The extruded bars were severe plastically deformed at 250C by swaging. Swaging refined further the grain size depending on the deformation ratio (number of passes). At optimal processing conditions the grain size was 450 nm and 570 nm for the AZ80 and ZK60 alloys, respectively.

Acoustic-Emission Study of Intermittency of Plastic Flow during Twinning and Dislocation Glide

64%

Shashkov I., Lebedkina T., Lebyodkin M., Dobron P., Chmelik F., Kral R., Parfenenko K., Mathis K.

Acta Physica Polonica A

2012

vol. 122

issue 3

430-434

Recent studies of plastic deformation with the aid of acoustic emission techniques proved an intermittent, scale-invariant character of plastic processes, as reflected in power-law statistical distributions. In some cases, the power-law exponents display close values leading to hypothesis of universality of scaling laws for various mechanisms of plasticity. Nevertheless, the accurate determination of the power law may be impeded by some sources of errors inevitable in real conditions, in particular, by superposition of individual acoustic emission events. In the present work, the sensitivity of the apparent statistics to the variation of the parameters of individualization of acoustic emission events is examined using Mg and Al based alloys. Both these alloys exhibit a highly cooperative character of plastic deformation, leading to strong acoustic activity which is governed by distinct microscopic mechanisms - mechanical twinning and the Portevin-Le Chatelier effect, respectively.

Refine search results

3 Acta Physica Polonica A

3 2012

3 Kral R.

2 Wagner L.

1 Chmelik F.

1 Dobron P.

1 Janecek M.

1 Janeček M.

1 Lebedkina T.

1 Lebyodkin M.

1 Mathis K.

1 Minárik P.

1 Oo M.

1 Parfenenko K.

1 Ryspaev T.

1 Shashkov I.

1 Wesling V.

Search results

Annealing Effects after Various Thermo-Mechanical Treatments on Microstructure and Mechanical Properties of Wrought Magnesium Alloy ZK60

Grain Refinement after Various Thermo-Mechanical Treatments in AZ80 and ZK60 Magnesium Alloys

Acoustic-Emission Study of Intermittency of Plastic Flow during Twinning and Dislocation Glide