Effect of Nb Alloying Addition on Local Phase Transformation at Microtwin Boundaries in Nickel-Based Superalloys

被引：16

作者：

Egan, A. J. ^{[1
,2
]}

Rao, Y. ^{[1
]}

Viswanathan, G. B. ^{[1
,2
]}

Smith, T. M. ^{[3
]}

Ghazisaeidi, M. ^{[1
]}

Tin, S. ^{[4
]}

Mills, M. J. ^{[1
,2
]}

机构：

[1] Ohio State Univ, Dept Mat Sci & Engn, 177 Watts Hall,2041 N Coll Rd, Columbus, OH 43210 USA

[2] Ohio State Univ, Ctr Electron Microscopy & Anal, Columbus, OH 43212 USA

[3] NASA Glenn Res Ctr, 21000 Brookpark Rd, Cleveland, OH 44135 USA

[4] Illinois Inst Technol, 10 W 32nd St, Chicago, IL 60616 USA

来源：

SUPERALLOYS 2020 | 2020年

基金：

美国国家科学基金会;

关键词：

Local phase transformation; Creep; Microtwin; HAADF; STEM; NI-BASED SUPERALLOYS; INTERMEDIATE TEMPERATURES; STACKING-FAULTS; CREEP; SEGREGATION; MECHANISM; MO; MICROSTRUCTURE; TA;

D O I：

10.1007/978-3-030-51834-9_62

中图分类号：

TF [冶金工业];

学科分类号：

0806 ;

摘要：

This work investigates two nominally similar polycrystalline alloys, with a subtle difference in Nb content, intended to elucidate its effect on local phase transformation strengthening during high temperature creep. Tests were conducted at 750 degrees C and 600 MPa to target the creep regime dominated by superlattice intrinsic and extrinsic stacking faults, as well as microtwinning. Alloy A, with higher Nb and lower Al, was found to be superior in creep strength to Alloy B, with lower Nb and higher Al, as well as previously investigated ME3 and LSHR. Atomic resolution scanning transmission electron microscopy and energy-dispersive spectroscopy found that this increased creep strength was due to a novel local phase transformation occurring along microtwin boundary interfaces as a result of the Nb increase. Complementary density functional theory calculations helped to confirm that this was chi phase formation. It is hypothesized that this transformation was the cause of the increased creep strength exhibited by Alloy A.

引用

页码：640 / 650

页数：11

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