Heat Treatment Effect on Microstructure and Mechanical Properties of Re-Containing Inconel 718 Alloy

DOI: 10.4236/jmmce.2012.119090   PDF   HTML     6,730 Downloads   9,833 Views   Citations


The effect of Rhenium additions to the standard Inconel 718 (ST IN718) alloy as well as solution and aging treatments on microstructure and hardness property were studied. The microstructure of Re-containing alloys has higher volume fraction of δ phase than standard alloy. Conventional solution treatment (CST) at 1273 K for 1h precipitates a thin film of δ phase at the grain boundaries as well as needle-like in γ matrix; however, after modified solution at 1440 K for 3 h long, both types of δ phase precipitates entirely vanish from the microstructure. Small colonies of needle-like δ phase start to appear with aging at 1023 K for 4 h, after CST. Prolonging the aging time to 50 h, these colonies enlarge in size and spread in the matrix. XRD and TEM observations were used to identify the precipitation of hard γ” and γ’ phases. The changing in hardness measurements were evidence about the precipitation of these hard phases. CST have higher rate to increase in hardness with aging time comparing to modified solution specimens.

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N. El-Bagoury and M. Ramadan, "Heat Treatment Effect on Microstructure and Mechanical Properties of Re-Containing Inconel 718 Alloy," Journal of Minerals and Materials Characterization and Engineering, Vol. 11 No. 9, 2012, pp. 924-930. doi: 10.4236/jmmce.2012.119090.

Conflicts of Interest

The authors declare no conflicts of interest.


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