Effect of LASER shock peening on microstructure, mechanical properties and corrosion behavior of interstitial free steel

• Published in: Surface & coatings technology 2015-10, Vol.280, p.216-224
• Main Authors: Shadangi, Y., Chattopadhyay, K., Rai, S.B., Singh, V.
• Format: Article
• Language: English
• Subjects: Corrosion behavior; Hardness; IF steel; Interstitial free steels; LASER shock peening; Laser shock processing; Microhardness; Microstructure; Peening; Tensile properties; Tensile strength
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2015.09.014

LASER shock peening (LSP) is an effective process of surface modification. This work is concerned with the effect of LSP on the modification of microstructure, hardness, microhardness profile, residual stress, tensile properties and corrosion behavior of interstitial free (IF) steel. In order to study the effect of pulse energy on hardness, samples were subjected to LSP at pulse energy of 170, 230, 290 and 340mJ respectively. The effect of LSP time on hardness, microhardness profile and tensile properties was investigated by processing the samples for 5, 10, 15 and 20min at pulse energy of 230mJ and there was found to be significant increase in tensile strength. There was grain refinement to nano level in the surface region due to LSP. Hardness was observed to increase by LSP up to 10min and tensile strength increased up to LSP of 5min. However with the increase in LSP time beyond 10min there was prominent ablation and melting. The effect of overlapped (OV) LASER shocks was also studied by comparing their behavior with that of single shock. The potentiodynamic polarization study showed significant increase in corrosion resistance of the LSPed IF steel. •LASER shock peening of interstitial free (IF) steel give best results in respect of mechanical properties and corrosion resistance in 3.5% NaCl solution in water with 5min overlapping of LASER shocks.•Bulk hardness was found to be increased by ~30% after LSP.•LSP was found to effectively modify the microstructure up to 1600μm and compressive residual stresses were observed up to 1200μm (for 5min overlapped LSP).•There was significant increase in the 0.2% yield strength, to the extent of ~80% and 104% following LASER shock peening of IF steel for 5/10min and 5min overlapped LSP respectively.•Corrosion resistance of 5min LSPed sample was ~90% greater than that of the as received sample.