Microstructure and hardness evolution in MAR-M247 Ni-based superalloy processed by controlled cooling and double heat treatment

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• 作者：Mehdi Rahimian ; ^{mehdi.rahimian@imdea.org} ; Srdjan Milenkovic ; Ilchat Sabirov
• 关键词：High-temperature alloys ; Precipitation ; Grain boundaries ; microstructure ; Metallography
• 刊名：Journal of Alloys and Compounds
• 出版年：2013
• 出版时间：15 February, 2013
• 年：2013
• 卷：550
• 期：Complete
• 页码：339-344
• 全文大小：1243 K

文摘

This work studies the microstructure and hardness evolution in MAR-M247 Ni-based superalloy processed by controlled cooling and double heat treatment. The solidification experiments with controlled cooling rates in the range of 0.25-10 K/s were carried out using GLEEBLE thermo-mechanical simulator. In the as-solidified material, with increasing cooling rate, grain and carbide size decreased, whereas volume fraction of carbides and microhardness increased. The as-solidified samples were subjected to a double heat treatment consisting of solution treatment followed by aging. The double heat treatment did not affect much the microstructure evolved in the sample solidified at 0.25 K/s while it led to dissolution of the ¦Ã/MC eutectic in the samples solidified with the cooling rates of 5 and 10 K/s. No significant effect of the double heat treatment on grain size, size and volume fraction of carbides is seen in all samples. The processing - microstructure-microhardness relationship in the material is discussed.