Effect of shape variations on the structure and crystallography of directionally solidified {gamma}/{gamma}{prime}-{alpha} eutectic composites
- Slovak Academy of Sciences, Bratislava (Slovakia). Institute of Materials and Machine Mechanics
Master ingots of the {gamma}/{gamma}{prime}-{alpha} alloy with chemical composition: Ni-31.01Mo-6.43Al-0.01W-0.006C-0.001S (wt.%) were prepared in a vacuum inducing furnace by melting high-purity metals under an argon atmosphere and casting in copper chill molds. These ingots were machined to rods of 12 {times} 10{sup {minus}3} m diameter. Directional solidification was performed under an argon atmosphere in a modified Bridgman-type solidification apparatus. During steady-state growth of the {gamma}/{gamma}{prime}-{alpha} eutectic composite the interfibre spacing varies with the growth rate according to the relation {lambda} = KR{sup {minus}0.5}, where K is calculated to be 4.71 {times} 10{sup {minus}9} m{sup 1.5}s{sup {minus}0.5}. The gradual contraction in the solidifying cross section decreases the number of the eutectic grains increases the interfibre spacing and causes coarsening and fiber-lamella transformations of the reinforcing phase. The phases grow in the <100> growth direction and the preferred {l_brace}100{r_brace}{sub {gamma}/{gamma}{prime}}{parallel}{l_brace}100{r_brace}{sub {alpha}} orientation relationship is maintained between the matrix and reinforcing phase. The <100> growth direction is parallel to the ingot axis for the matrix but deviates from this axis for the reinforcing phase.
- OSTI ID:
- 103591
- Journal Information:
- Scripta Metallurgica et Materialia, Journal Name: Scripta Metallurgica et Materialia Journal Issue: 3 Vol. 33; ISSN SCRMEX; ISSN 0956-716X
- Country of Publication:
- United States
- Language:
- English
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