ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Effects of atmosphere and specimen geometry on thermal fatigue (TF) crack initiationand propagation in a low Si content hot work tool steel X38CrMoV5-47HRC were investigated.The TF specimen’s geometry enhances the uni-axial TF loading conditions. A high frequencyinduction heating (3 to 4 MHz) is used. A new TF rig, working under air and/or inert atmospherewith reduced PO2 has been set up. The reduction of PO2 results in localized oxidation sites. Whatevergeometry and atmosphere conditions, TF cracks initiate exclusively in the oxide layers. Damagemechanisms are environment dependant. Under laboratory air, parallel macroscopic cracks initiateperpendicular to the hoop stress. Under argon and nitrogen, SEM surface observations show thatinitiated cracks coalesce by zigzagging along crystallographic paths between non-oxidized zones.In-depth crack propagation mechanism is mainly trans-granular. TF crack initiation life under airand in presence of Fe-Al intermetalllics is decreased in comparison to inert atmosphere
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/20/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.595-598.789.pdf
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