Microstructural Stability and Creep Response of a New Al-Fe-W-Si Alloy.
Abstract
The microstructural stability and creep properties of a new aluminum alloy for potential aerospace applications at service temperatures up to 700 F (371 C) were evaluated. The Al alloy composition is 11.50% iron, 3.75% tungsten and 2.25% silicon by weight. The material was rapidly solidified via planar flow casting, vacuum hot-pressed, and then extruded into bar form. The room temperature yield strength and ultimate tensile strength are 603 MPa and 626 MPa, respectively, with an 11.3% elongation and a 33.0% reduction of area at fracture. A series of creep experiments were performed on this alloy at 700 F (371 C), and the results were compared to alloys FVS0812 (8009) and FVS1212. A change in creep deformation mechanism was discovered at a stress level of approximately 85 MPa defining the maximum allowable stress for components made from this material. The microstructural stability was evaluated by aging samples at either 700 F (371 C) or 900 F (482 C) and measuring the average grain and dispersoid sizes as a function of aging time with transmission electron microscopy. Upon aging at 371 C, the room temperature hardness did not change even after times greater than 1000 hrs., indicating the microstructure is stable at this temperature. The hardness decreased slightly during 482 C aging over a period of 670 hrs. indicating minor microstructural changes (e.g., dispersoid coarsening) were occurring over long periods of time.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1991
- Accession Number
- ADA239861
Entities
People
- John Benci
- William Frazier
Organizations
- Naval Air Warfare Center Warminster