Microstructural and mechanical characterization of tungsten containing lanthana based ferritic ODS steel

In the present study, tungsten (W) containing lanthana (La2O3) based ODS steels (Fe-14Cr-1Ti-xW-0.5L(2)O(3) or 14LWT, x = 0, 0.5, 1, 1.5, 2) have been synthesized by mechanical alloying followed by spark plasma sintering (SPS). The effect of the tungsten content and sintering temperature (1050 degrees C and 1100 degrees C) on the densification and mechanical properties of the alloys have been evaluated and correlated with the microstructure. Increasing the sintering temperature leads to improvement of both the density and the hardness. The highest hardness and Young's modulus were obtained for Fe-14Cr-1Ti-1W-0.5L(2)O(3) as 1061.4 +/- 22.8 HV and 228.2 +/- 2.9 GPa, respectively. Transmission Electron Microscopy (TEM) analysis suggested that the nano-sized precipitates are complex oxides of La, Ti and Cr (i.e., La-Ti-Cr-O) and are predominantly in the size range of 2-5 nm. Com-parison of properties of 14LWT with Fe-14Cr-1Ti-1W-0.5Y(2)O(3) (14YWT) ODS steel showed that the 14LWT exhibits higher hardness and compressive strength.

Automated summary

In this study, tungsten and lanthana containing ODS steels were synthesized by mechanical alloying and spark plasma sintering. The results showed that increasing sintering temperature improved both the density and hardness of the alloys. Transmission Electron Microscopy analysis revealed nano-sized precipitates composed of La, Ti, and Cr. Comparisons with other ODS steels demonstrated that the tungsten containing alloy exhibited higher hardness and compressive strength.