Micro/nanometre grain sizes appear to improve the biocompatibility of austenitic stainless steel. In order to realise the reverse transformation (from strain-induced martensite) austenite structure control with micro/nanometre size, the influence of annealing parameters on the microstructure evolution and mechanical properties of 316L-Nb austenitic stainless steel were investigated. Furthermore, the role of Nb in the annealing process was also studied. The results showed that the closely 100% reversion transformation austenite structures were obtained in the samples after annealing at 850°C, where the grains with the grain diameter ≤500 nm accounted for 25% and the grains with the grain diameter >0.5 µm accounted for 75%. The micro/nanometre grain steel not only exhibited a high strength level but also exhibited a desirable elongation. Moreover, the Nb demonstrates a remarkable effect on grain-refining and a significant role in improving the stability of the microstructure.
MisraR. D. K., Thein-HanW. W., PesacretaT. C., SomaniM. C. and KarjalainenL. P.: ‘Biological significance of nanograined/ultrafine-grained structures: interaction with fibroblasts’, Acta Biomater., 2010, 6, 3339–3348. doi: 10.1016/j.actbio.2010.01.034
2.
MisraR. D. K., Thein-HanW. W., MaliS. A., SomaniM. C. and KarjalainenL. P.: ‘Cellular activity of bioactive nanograined/ultrafine-grained materials’, Acta Biomater., 2010, 6, 2826–2835. doi: 10.1016/j.actbio.2009.12.017
3.
MaliS., MisraR. D. K., SomaniM. C. and KarjalainenL. P.: ‘Biomimetic nanostructured coatings on nano-grained/ultrafine-grained substrate: Microstructure, surface adhesion strength, and biosolubility’, Mater. Sci. Eng. C, 2009, 29, 2417–2427. doi: 10.1016/j.msec.2009.07.003
4.
VenkatsuryaP. K. C., Thein-HanW. W., MisraR. D. K., SomaniM. C. and KarjalainenL. P.: ‘Advancing nanograined/ultrafine-grained structures for metal implant technology: interplay between grooving of nano/ultrafine grains and cellular response’, Mater. Sci. Eng. C, 2010, 30, 1050–1059. doi: 10.1016/j.msec.2010.05.008
5.
MisraR. D. K., Ravi KumarB., SomaniM. and KarjalainenP.: ‘Deformation processes during tensile straining of ultrafine/nanograined structures formed by reversion in metastable austenitic steels’, Scr. Mater., 2008, 59, 79–82. doi: 10.1016/j.scriptamat.2008.02.028
6.
HwangB. and LeeC. G.: ‘Influence of thermomechanical processing and heat treatments on tensile and Charpy impact properties of B and Cu bearing high-strength low-alloy steels’, Mater. Sci. Eng. A, 2010, 527, 4341–4346. doi: 10.1016/j.msea.2010.03.106
7.
MuszkaK., HodgsonP. D. and MajtaJ.: ‘Study of the effect of grain size on the dynamic mechanical properties of microalloyed steels’, Mater. Sci. Eng. A, 2009, 500, 25–33. doi: 10.1016/j.msea.2008.09.069
8.
YakubtsovI. A., PoruksP. and BoydJ. D.: ‘Microstructure and mechanical properties of bainitic low carbon high strength plate steels’, Mater. Sci. Eng. A, 2008, 480, 109–116. doi: 10.1016/j.msea.2007.06.069
9.
WengY. Q.: ‘Achievements of N. G. Steels program in China’, in Proceedings of ‘Second International Conference on Advanced Structural Steels’, Shanghai, 2004, 1–14.
10.
WuH. B., WuF. J., YangS. W. and TangD.: ‘The formation mechanism of austenite structure with micro/sub-micrometer bimodal grain size distribution’, Acta Metall. Sin., 2014, 50, (3), 269–274.
11.
UnfriedJ. S., GarzónC. M. and GiraldoJ. E.: ‘Numerical and experimental analysis of microstructure evolution during arc welding in armor plate steels’, J. Mater. Process. Technol., 2009, 209, 1688–1700. doi: 10.1016/j.jmatprotec.2008.04.025
12.
WuH. B., YangS. W., YuanS. Q., ShangC. J., WangX. M. and HeX. L.: ‘Evolution of microstructures in a low carbon bainitic steel during reheating’, Mater. Sci. Forum, 2005, 475–479, 121–124.
13.
YangS. W., ShangC. J., HeX. L., WangX. M. and YuanY.: ‘Stability of ultra-fine microstructures during tempering’, J. Univ. Sci. Technol. Beijing, 2001, 8, 119–124.
14.
KiskoA., HamadaA. S., TalonenJ., PorterD. and KarjalainenL. P.: ‘Effects of reversion and recrystallization on microstructure and mechanical properties of Nb-alloyed low-Ni high-Mn austenitic stainless steels’, Mater. Sci. Eng. A, 2016, 657, 359–370. doi: 10.1016/j.msea.2016.01.093
15.
ForouzanF., NajafizadehA., KermanpurA., HedayatiA. and SurkialiabadR.: ‘Production of nano/submicron grained AISI 304L stainless steel through the martensite reversion process’, Mater. Sci. Eng. A, 2010, 527, 7334–7339. doi: 10.1016/j.msea.2010.08.002
16.
ZhongN., WangX. D., WangL. and RongY. H.: ‘Enhancement of the mechanical properties of a Nb-microalloyed advanced high-strength steel treated by quenching–partitioning–tempering process’, Mater. Sci. Eng. A, 2009, 506, (1), 111–116. doi: 10.1016/j.msea.2008.11.014
17.
ZhouW. H., ChallaV. S. A., GuoH., ShangC. J. and MisraR. D. K.: ‘Structure–mechanical property relationship in a low carbon Nb–Cu microalloyed steel processed through a three-step heat treatment: The effect of tempering process’, Mater. Sci. Eng. A, 2015, 620, 454–462. doi: 10.1016/j.msea.2014.09.079
18.
GómezM., MedinaS. F. and VallesP.: ‘Determination of driving and pinning forces for static recrystallization during hot rolling of a niobium microalloyed steel’, ISIJ Int., 2005, 45, (11), 1711–1720. doi: 10.2355/isijinternational.45.1711
19.
ShaQ. and SunZ.: ‘Grain growth behavior of coarse-grained austenite in a Nb–V–Ti microalloyed steel’, Mater. Sci. Eng. A, 2009, 523, 77–84. doi: 10.1016/j.msea.2009.05.037
