Woodruff School of Mechanical Engineering

COE/Structural Mechanics Seminar

Title:

Research progress of novel Co-base single crystal superalloys

Speaker:

Dr. Qiang (Charles) Feng

Affiliation:

University of Science and Technology, Beijing

When:

Monday, June 29, 2015 at 3:00:00 PM

Where:

MRDC Building, Room 4211

Host:

Dr. David McDowell
david.mcdowell@me.gatech.edu

Abstract

In recent years, the discovery of high-temperature stable γ'-Co3(Al, W) in Co-Al-W-base alloys may provide new possibility for developing new generation Co-based superalloys strengthened by γ' precipitates. To date, it is chanllenged for Co-Al-W-base alloys to enhance mechanical properties by enlarging the γ/γ' two-phase region and improving the γ/γ' microstructural stability at elevated temperature. Our previous study indicated that the individual addition of Ti and Ta had positive effects on γ' solvus temperature and microstructural stability. In the current work, the independent and interaction of Ti and Ta on microstructural stability, creep property and oxidation resistance of single crystal Co-Al-W-base alloys were investigated. The γ′ solvus temperatures in Co-Al-W-base alloys were improved significantly by the coupling effect of Ti and Ta addition. The γ/γ′ two-phase microstructure still remained with a γ′ volume fraction about 63% at 1050oC for 1000h. The addition of Ti show the distinctive better oxidation resistance than Ta addition. Furthermore, the creep property of single-crystal alloys containing Ti and Ta was superior to other reported Co-Al-W-base alloys and 1st commercial Ni-base single-crystal superalloys at 1000oC. The creep deformation mechanism associated with the stacking fault and anti-phase boundary was discussed. The current study is helpful for future alloy design and improving the temperature capability of γ'-strengthened Co-base superalloys


Biography

Dr. Qiang (Charles) Feng is the Professor of the State Key Laboratory for Advanced Metals and Materials at the University of Science and Technology, Beijing (USTB). He graduated with the B.S./M.S. degree from USTB in 1991/1994, and received his Ph.D. degree from Polytechnic Institute of New York University in 2000. He had been working as the Postdoctoral Research Fellow and Senior Research Fellow in the Department of Materials Science and Engineering at the University of Michigan from 2000 to 2005. Professor Feng has authored or co-authored over 80 papers in referred journals and conference proceedings, and his research interests focus on alloy development, microstructure, mechanical property (creep and fatigue) and life prediction of high temperature structural materials, including superalloys, intermetallic alloys and heat resistant steels. Materials systems of interests are mainly applied in aircraft engine and gas turbine industries as well as power generation industries and automotive industries.