Understanding the creep property of heat-resistant Al alloy by analyzing eutectic phase/matrix interface structures

Figures & data

Figure 1. Microstructure characteristics: (a) AlFeNi; (b) AlFeNi-0.2Sc. (c) Sc concentration in different areas. Al₃Sc distribution in different zones of the AlFeNi-0.2Sc alloy at peak-aged state: (d) Eutectic boundary Al; (e) Eutectic internal Al.

Figure 2. (a, c) Eutectic phase inside grains of the AlFeNi-0.2Sc alloy at peak-aged state; (b) Element distributions around the eutectic phase; (d) Overall morphology of the precipitate at Position A near the Al/Al₉FeNi interface; (e) HRTEM image at Position A.

Table 1. Element contents (at%) of featured points at the eutectic phase and surrounding area of AlFeNi-0.2Sc alloy at peak-aged state.

Position	Al (at%)	Fe (at%)	Ni (at%)	Sc (at%)
1	91.21	3.67	2.95	2.18
2	95.74	0.88	1.32	2.06
3	84.71	0.55	8.51	6.23
4	100	/	/	/
5	83.07	10.07	6.87	/

Figure 3. (a) Al/Al₉FeNi interface and crystalline orientation of each phase under this axis; (b) Lattice structure of Al₉FeNi under the [0$\overline{1}$0] axis; (c) Schematic diagram of OR1; (d) Lattice structure of (11$\overline{1}$)_Al; (e) Lattice structure of (00$\overline{1}$)_Al9FeNi; (f) Interface structure from the side view; (g) Schematic diagram of Sc precipitation in the interface structure.

Figure 4. (a) Comparison of the creep behavior of Al alloys at 300°C; (b) Comparison of the dislocation creep behavior of AlFeNi alloy at 300°C; (c) Schematic diagram of Al₃Sc precipitates under peak aging; (d) Interaction between dislocation and matrix precipitates; (e) FEM Simulation of stress distribution after the formation of transition layer around the eutectic phase; (f) Al₃Sc precipitate layer around the eutectic phase and the lattice strain around the interface calculated by GPA: (g) Vertical interface; (h) Along interface (The white arrow points at the Al/Al₉FeNi interface; the red circle marks the Al₃Sc interface precipitate).