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Title: The influence of Mg on creep properties and fracture behaviors of Mar-M247 superalloy under 1255 K/200 MPa

Abstract

The effects of Mg microadditions on the high-temperature/low stress (1,255 K/200 MPa) creep properties and fracture behavior of a Mar-M247 supralloy were investigated in this study. The results of quantitative statistical analyses showed that when Mg microadditions up to 50 ppm were made, the MC carbides located at grain boundaries (designated GB MC) were significantly refined and spheroidized and the number of MC carbides decreased. In addition, the M{sub 23}C{sub 6} carbides present on GBs dramatically increased with increasing Mg contents up to 50 ppm, and the creep resistance was enhanced under the test condition of 1,255 K/200 MPa. However, the creep performance of a Mar-M247 superalloy containing 80 ppm Mg deteriorated due to the formation of an extremely large amount of MC carbide and a decrease in the number of M{sub 23}C{sub 6} carbides at GBs. The cracks mainly initiated and propagated along GBs in both the Mg-free and Mg-containing Mar-M247 superalloys under 1,255 K/200 MPa, and the final rupture was caused by intergranular fracture. Under the present creep condition, the optimal Mg microaddition to a Mar-M247 superalloy should be 30 to 50 ppm.

Authors:
; ;
Publication Date:
Research Org.:
Chung-Shan Inst. of Science and Tech. (TW)
OSTI Identifier:
20075679
Alternate Identifier(s):
OSTI ID: 20075679
Resource Type:
Journal Article
Journal Name:
Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science
Additional Journal Information:
Journal Volume: 31; Journal Issue: 5; Other Information: PBD: May 2000; Journal ID: ISSN 1073-5623
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; MICROSTRUCTURE; CREEP; FRACTURE PROPERTIES; HEAT RESISTING ALLOYS; MAGNESIUM ADDITIONS; METALLURGICAL EFFECTS; CARBIDES; ELECTRON MICROSCOPY

Citation Formats

Bor, H.Y., Chao, C.G., and Ma, C.Y. The influence of Mg on creep properties and fracture behaviors of Mar-M247 superalloy under 1255 K/200 MPa. United States: N. p., 2000. Web. doi:10.1007/s11661-000-0255-3.
Bor, H.Y., Chao, C.G., & Ma, C.Y. The influence of Mg on creep properties and fracture behaviors of Mar-M247 superalloy under 1255 K/200 MPa. United States. doi:10.1007/s11661-000-0255-3.
Bor, H.Y., Chao, C.G., and Ma, C.Y. Mon . "The influence of Mg on creep properties and fracture behaviors of Mar-M247 superalloy under 1255 K/200 MPa". United States. doi:10.1007/s11661-000-0255-3.
@article{osti_20075679,
title = {The influence of Mg on creep properties and fracture behaviors of Mar-M247 superalloy under 1255 K/200 MPa},
author = {Bor, H.Y. and Chao, C.G. and Ma, C.Y.},
abstractNote = {The effects of Mg microadditions on the high-temperature/low stress (1,255 K/200 MPa) creep properties and fracture behavior of a Mar-M247 supralloy were investigated in this study. The results of quantitative statistical analyses showed that when Mg microadditions up to 50 ppm were made, the MC carbides located at grain boundaries (designated GB MC) were significantly refined and spheroidized and the number of MC carbides decreased. In addition, the M{sub 23}C{sub 6} carbides present on GBs dramatically increased with increasing Mg contents up to 50 ppm, and the creep resistance was enhanced under the test condition of 1,255 K/200 MPa. However, the creep performance of a Mar-M247 superalloy containing 80 ppm Mg deteriorated due to the formation of an extremely large amount of MC carbide and a decrease in the number of M{sub 23}C{sub 6} carbides at GBs. The cracks mainly initiated and propagated along GBs in both the Mg-free and Mg-containing Mar-M247 superalloys under 1,255 K/200 MPa, and the final rupture was caused by intergranular fracture. Under the present creep condition, the optimal Mg microaddition to a Mar-M247 superalloy should be 30 to 50 ppm.},
doi = {10.1007/s11661-000-0255-3},
journal = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science},
issn = {1073-5623},
number = 5,
volume = 31,
place = {United States},
year = {2000},
month = {5}
}