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The impact resistance of silicon (Si)-containing modified 9Cr-1Mo steels has been investigated within a temperature regime of -40 to 440°C using the Charpy method. The results indicate that the energies absorbed in fracturing the tested specimens were substantially lower at temperatures of -40, 25, and 75°C compared to those at elevated temperatures. Lower impact energies and higher ductile-to-brittle-transition-temperatures (DBTTs) were observed with the steels containing 1.5 and 1.9 wt.% Si. The steels containing higher Si levels exhibited both ductile and brittle failures at elevated temperatures. However, at lower temperatures, brittle failures characterized by cleavage and intergranular cracking were observed for all four tested materials.


Chromium-iron alloys; DBTT; Fractography; High temperatures; Impact; Impact energy; Iron-molybdenum alloys; Silicon effect; Silicon steel; Steel alloys – Brittleness; Steel alloys – Fatigue; Steel alloys – Fracture; T91 grade steels


Materials Science and Engineering | Mechanical Engineering | Mechanics of Materials | Metallurgy


Copyright 2009 ASM International. This paper was published in Journal of Materials Engineering and Performance, Vol. 18, Issue 2, pp. 205-210 and is made available as an electronic reprint with the permission of ASM International. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplications of any material in this paper for a fee or for commercial purposes, or modification of the content of this paper are prohibited.

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