The ferritic-austenitic duplex steels are equipped with a mechanical-technological combination of properties, which is advantageous compared to the features of stainless completely ferritic or completely austenite steels. The duplex steels crystallize by fully ferritic or ferriticaustenite solidification with the austenite precipitation due to the solid solution reactions during the further cooling. To adjust the ferrite-austenite ratio, the steels must be heat treated by temperatures above the field of precipitation stability, followed by water quenching. The temperature and the time of the heat treatment effect the element distribution according to their higher solubility in the ferritic or austenitic phases. The typical microstructure of the duplex stainless steels can only be realized due to deformation and recrystallisation processing.

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The objective of designing a biocompatible and mechanically stable scaffold for hard tissue regeneration was achieved by fabricating diopside/forsterite composites. Superior mechanical strength, slow degradation, excellent antibacterial activity and good cell viability were attained with the increase in forsterite ratio in the composites whereas apatite deposition ability got enhanced as the diopside content was increased. The variation in the rate of apatite deposition on the surface of composites exhibited different surface topography such as nano-structured interconnected fibrous network and globular morphology. The scaffolds after one-month immersion in a physiological environment exhibited good Young's modulus and compressive strength. Clear and distinguishable prevention of bacterial growth confirms that composites have the potential to inhibit microbial colony formation of nine different clinical pathogens. The composite containing major diopside content was more effective toward S. aureus while the growth of E. coli was inhibited more by the composite containing a higher ratio of forsterite. The interaction of composites with MG-63 cells showed an enhancement in cell viability as the content of forsterite was increased. MTS assay confirmed the cytocompatibility of samples with negligible toxicity effects.