11. Because austempering does not produce martensite , the steel does not require further tempering. 12. This reduces the amount of total martensite by changing some of it to ferrite. 13. The range of alloys available produced either mixed microstructures or excessive amounts of Martensite . 14. A tempered outer ring of martensite , 2. 15. This turns the heated portion into very hard martensite , but leaves the rest unchanged. 16. Davenport and Bain originally described the microstructure as being similar in appearance to tempered martensite . 17. Further heating reduces the martensite even more, transforming the unstable carbides into stable cementite. 18. Howe and Foley investigated the hardening of steel and the formation and tempering of martensite . 19. Since ductile FeNi martensites are formed upon cooling, cracks are non-existent or negligible. 20. The R-phase is another martensitic phase that competes with the martensite phase mentioned above.
