Publication detail

Initiation of fatigue cracks in AZ91 Mg alloy processed by ECAP

FINTOVÁ, S. KUNZ, L.

Original Title

Initiation of fatigue cracks in AZ91 Mg alloy processed by ECAP

English Title

Initiation of fatigue cracks in AZ91 Mg alloy processed by ECAP

Type

conference paper

Language

en

Original Abstract

Mechanism of fatigue crack initiation was investigated in ultrafine-grained (UFG) magnesium alloy AZ91 processed by equal channel angular pressing (ECAP). Fatigue behaviour of UFG material was compared to the behaviour of material in an initial as-cast state. Focused ion beam technique (FIB) was applied to reveal the surface relief and early fatigue cracks. Two substantially different mechanisms of crack initiation were observed in UFG structure, which can be characterized as bimodal even after 6 ECAP passes by route Bc. The bimodality consists in a coexistence of very fine grained areas with higher content of Mg17Al12 particles and areas exhibiting somewhat larger grains and lower density of particles. The fatigue cracks which initiate in areas of larger grains are related to the cyclic slip bands; this initiation mechanism is similar to that observed in cast alloy. The second initiation mechanism is related to the grain boundary cracking which takes place predominantly in the fine grained areas.

English abstract

Mechanism of fatigue crack initiation was investigated in ultrafine-grained (UFG) magnesium alloy AZ91 processed by equal channel angular pressing (ECAP). Fatigue behaviour of UFG material was compared to the behaviour of material in an initial as-cast state. Focused ion beam technique (FIB) was applied to reveal the surface relief and early fatigue cracks. Two substantially different mechanisms of crack initiation were observed in UFG structure, which can be characterized as bimodal even after 6 ECAP passes by route Bc. The bimodality consists in a coexistence of very fine grained areas with higher content of Mg17Al12 particles and areas exhibiting somewhat larger grains and lower density of particles. The fatigue cracks which initiate in areas of larger grains are related to the cyclic slip bands; this initiation mechanism is similar to that observed in cast alloy. The second initiation mechanism is related to the grain boundary cracking which takes place predominantly in the fine grained areas.

Keywords

fatigue crack initiation, fatigue, AZ91 magnesium alloy

RIV year

2014

Released

08.08.2014

Publisher

IOP Publishing

ISBN

978-1-63439-874-9

Book

NANOMATERIALS BY SEVERE PLASTIC DEFORMATION. INTERNATIONAL CONFERENCE. 6TH 2014. (NanoSPD6) (2 PARTS)

Pages from

1

Pages to

8

Pages count

8

URL

Full text in the Digital Library

BibTex


@inproceedings{BUT110649,
  author="Stanislava {Fintová} and Ludvík {Kunz}",
  title="Initiation of fatigue cracks in AZ91 Mg alloy processed by ECAP",
  annote="Mechanism of fatigue crack initiation was investigated in ultrafine-grained (UFG)
magnesium alloy AZ91 processed by equal channel angular pressing (ECAP). Fatigue behaviour
of UFG material was compared to the behaviour of material in an initial as-cast state. Focused
ion beam technique (FIB) was applied to reveal the surface relief and early fatigue cracks.
Two substantially different mechanisms of crack initiation were observed in UFG structure,
which can be characterized as bimodal even after 6 ECAP passes by route Bc. The bimodality
consists in a coexistence of very fine grained areas with higher content of Mg17Al12 particles and
areas exhibiting somewhat larger grains and lower density of particles. The fatigue cracks which
initiate in areas of larger grains are related to the cyclic slip bands; this initiation mechanism is
similar to that observed in cast alloy. The second initiation mechanism is related to the grain
boundary cracking which takes place predominantly in the fine grained areas.",
  address="IOP Publishing",
  booktitle="NANOMATERIALS BY SEVERE PLASTIC DEFORMATION. INTERNATIONAL CONFERENCE. 6TH 2014. (NanoSPD6) (2 PARTS)",
  chapter="110649",
  doi="10.1088/1757-899X/63/1/012159",
  howpublished="online",
  institution="IOP Publishing",
  number="8",
  year="2014",
  month="august",
  pages="1--8",
  publisher="IOP Publishing",
  type="conference paper"
}