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Evolution of Microstructures During Austempering of Ductile Irons Alloyed with Manganese and Copper

IR@CMERI: CSIR- Central Mechanical Engineering Research Institute (CMERI), Durgapur

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Title Evolution of Microstructures During Austempering of Ductile Irons Alloyed with Manganese and Copper
 
Creator Dasgupta, Ranjan Kumar
Mondal, Dipak Kumar
Chakrabarti, Ajit Kumar
 
Description The influences of relatively high manganese (0.45 through 1.0 wt pct) and copper (0.56 through 1.13 wt pct) contents on microstructure development and phase transformation in three austempered ductile irons have been studied. The experimental ductile irons alloyed with copper and manganese are found to be practically free from intercellular manganese segregation. This suggests that the positive segregation of manganese is largely neutralized by the negative segregation of copper when these alloying elements are added in appropriate proportions. The drop in unreacted austenite volume (UAV) with increasing austempering temperature and time is quite significant in irons alloyed with copper and manganese. The ausferrite morphology also undergoes a transition from lenticular to feathery appearance of increasing coarseness with the increasing austempering temperature and time. SEM micrographs of the austempered samples from the base alloy containing manganese only, as well as copper plus manganese-alloyed irons, clearly reveal the presence of some martensite along with retained austenite and ferrite. X-ray diffraction analysis also confirms the presence of these phases. SEM examination further reveals the presence of twinned martensite in the copper plus manganese-alloyed samples. The possibility of strain-induced transformation of austenite to martensite during austempering heat treatment is suggested.
 
Publisher Springer Link
 
Date 2013-03
 
Type Article
PeerReviewed
 
Identifier Dasgupta, Ranjan Kumar and Mondal, Dipak Kumar and Chakrabarti, Ajit Kumar (2013) Evolution of Microstructures During Austempering of Ductile Irons Alloyed with Manganese and Copper. Metallurgical and Materials Transactions A, 44 (3). pp. 1376-1387.
 
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