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Abstract: Pulse electrolysis was employed to deposit heterogeneous Cu–Co alloys from complexed sulphate–citrate electrolyte. The crystal structure, surface morphology and microstructure of the deposited alloys were analysed to understand the effect of process parameters on the deposit. X-ray and selected area electron diffraction (SAED) studies showed that as-deposited films were composed of two phases, a solid solution of face centred cubic Cu–Co phase and a hexagonal close packed Co phase. Pulse electrolysis and addition of saccharine within the electrolyte were found to enhance in forming two-phase structure. Surface morphology of the pulse current (PC) plated alloys was found to be smoother than their direct current (DC) counterparts. Presence of saccharine within the electrolyte led to further improvement in brightness of the deposits top layer. Microstructural investigations revealed that the deposited alloys were nanocrystalline in nature. Further refinement in grain size and increased homogeneity in microstructure were observed in the presence of saccharine. [Copyright &y& Elsevier]

Ultrahigh strength steel is designed for light-weight cost-effective parts with improved safety by dint of high strength coupled with better fuel efficiency for automotive and aerospace applications. The current steel with medium carbon (0.28 wt%) and alloying elements (∼8%) such as Mn, Ni, Mo along with micro-alloying of Ti and Nb has been processed by thermo-mechanical controlled processing with different finish rolling temperature (FRT) followed by air cooling and water quenching. Microstructure of air cooled specimen consists of lower bainite with a few amount of lath martensite, whereas a mixture of lath martensite and lower bainite in prior pan-caked austenite grains has also been obtained on water quenching. It is observed that microstructure becomes gradually finer with reduction of FRT for both cooling conditions and fine-scale carbide/carbonitride precipitates, enriched with Ti/Nb along with dislocation sub-structures within bainite and martensite laths have performed as strengtheners. Ultrahigh strength (1991–2032 MPa) with lower elongation (5–7%) is obtained in water quenched samples, whereas air cooled samples show comparatively lower strength (1841–1928 MPa) with marginally higher elongation (8–9%). Different strengthening mechanisms have been quantified which cumulatively contribute to the yield strength of the current steels. [ABSTRACT FROM AUTHOR]