D M DIMIDUK(Wright-Laboratory
,
Materials Directorate
,
WL/MLLM
,
Wright-Patterson AFB
,
OH45433-7817
,
USA)P R SUBRAMANIAN and M G MENDIRATTA (UES
,
Inc.
,
Dayton
,
OH 45432
,
USA)
金属学报(英文版)
Since the late 1980's there have been a number of research efforts aimed at exploring and developing the refractory intermetalllic materials for service at temperatures which compete with the nickel-based superalloys in structural applications. These efforts have documented the physical and mechanical properties of a broad set of compositions. However, only in the last three years have these efforts yielded sufficient experimental results on single selected systems to suggest that damage tolerance, creep resistance and oxidation resistance may be obtained and controlled simultaneously. These findings led to alloy development concepts and approaches which are currently under investigation and are expected to lead to research focused on a smaller set of alloys. An overview of selected alloy development strategies and resulting structural properties is presented herein.
关键词:
: refractory intermetallics
,
null
,
null
Young- Won (Y-W.) Kim(UES
,
Inc.
,
Materials Research Division
,
4401 Dayton-Xenia Rd.
,
Dayton
,
OH 45432
,
USA)(Paper presented at the International Workshop on OrderedIntermetallics 1992
,
Hangzhou
,
China)
材料科学技术（英）
The effects of microstructure on the deformation and fracture behaviour of two-phase TiAl alloys were investjgated under monotonic and cyclical loading conditions, over a range of temperatu res.The tensile behaviour is analyzed for deformation temperatures between RT and 950℃, Fracture resistance behaviour and toughening mechanisms at RT and 800℃ are analyzed. and the inverse relationship botween ductility and toughness is explained using the crack initiation toughness. The preliminary results of load-controlled fatigue behaviour at 800℃ are interpreted using the tensile behaviour because deformation structure and fracture modes are similar under these two loading conditions
关键词:
Young-Won KIM(UES
,
Inc.
,
Dayton
,
OH 45432
,
USA)
金属学报(英文版)
Unbalanced properties for both fine-grained gamma and coarse-grained lamellar microstructures typically produced in gamma alloys are described. Efforts for the improvements are reviewed along with some experimental results. Empirical improvements have been made in cast alloys, which have led gamma alloys to a viable materials technology and to the development of various application areas for gas turbine engines as well as automotive engines. Efforts to understand fundamental and applied aspects leading to the improvements are assessed for wrought alloys. Optimization of microstructures through process control,innovative heat treatments, alloy chemistry modification and their combinations have progressed in the endeavor. Similar efforts have just begun for cast alloys where work on fundamental understanding has been lagging. Future directions are suggested for further improvements and predicted for the development of higher temperature/performance alloys.
关键词:
: gamma TiAl
,
null
,
null
,
null
