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Strengthening of the Fe-Ni Invar Alloy Through Chromium

Invar alloys with both high strength and low thermal expansion are urgently needed in fields such as overhead power transmission, aero-molds, and so on. In this paper, Cr was introduced as a cost-efficient alloying element into the Fe-36Ni binary invar alloy to increase its mechanical strength. Our...

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Detalles Bibliográficos
Autores principales: Sui, Qingshuang, He, Jun, Zhang, Xin, Sun, Zhonghua, Zhang, Yunfei, Wu, Yingfei, Zhu, Zhixiang, Zhang, Qiang, Peng, Huifen
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6515356/
https://www.ncbi.nlm.nih.gov/pubmed/31010010
http://dx.doi.org/10.3390/ma12081297
Descripción
Sumario:Invar alloys with both high strength and low thermal expansion are urgently needed in fields such as overhead power transmission, aero-molds, and so on. In this paper, Cr was introduced as a cost-efficient alloying element into the Fe-36Ni binary invar alloy to increase its mechanical strength. Our results confirmed that fine Cr(7)C(3) precipitants, together with some Fe(3)C, in the invar alloy aged at 425 °C could be obtained with a short aging time. Those precipitants then grew and aggregated at grain or sub-grain boundaries with an increase in aging time. Simultaneously, mechanical strength and coefficient of thermal expansion (CTE) parabolically varied with the increase in aging time. The sample aged at 425 °C for 7 h presented a maximum strength of 644.4 MPa, together with a minimum coefficient of thermal expansion of 3.30 × 10(−6) K(−1) in the temperature range of 20–100 °C. This optimized result should be primarily attributed to the precipitation of the nanoscaled Cr(7)C(3).