In this work, epoxy resin composites reinforced with varying compositions (0 wt.%-20 wt.%) of cow horn (CH) and corn cob (CC) particles were developed. The microstructure, hardness and wear resistance of the composites were investigated. The microstructure analysis revealed that the CC appeared to be fibre-like while the CH appeared as particles in the epoxy resin matrix. The particles content and distribution were enhanced as the CH composition in the composites increased. Compared to the unreinforced sample, the composite started showing improvement in hardness at 6 wt.% CH content (10.1 HV). This increased with increase in CH content and maximum was found at 20 wt.% CH (18.6 HV). CC additions have no considerable influence on the composite hardness. The entire composites exhibited lower wear rate compared with the epoxy resin sample. The least wear rate was found at 20 wt.% CH. CH reinforcement enhanced the composite wear properties than the CC.

In this work, gas metal arc welding of AISI 304 stainless steel at varying compositions of argon-CO2 shielding environment was performed using an established optimum parametric combination. Thereafter, investigations on the microstructure of the welded joints and mechanical properties of the weldments were carried out. Weldments of excellent surface quality that are void of spatters and pores were obtained when the shielding gas composition (wt.%) range is between 100% argon and 75% argon - 25% CO2. Increasing percentage composition of CO2 beyond 25% resulted in irregular bead formation characterized with spatters and pores. The hardness of the welded joint became significantly high as the CO2 composition in the shielding gas increased. The highest value of 310 HV was obtained when the shielding gas composition was 5% argon- 95% CO2. The least (220 HV) was obtained when the shielding gas was 100% argon. High ultimate tensile strength (596 - 378 MPa) was achieved when the shielding gas composition range is between 100% argon and 75% argon-25% CO2. The UTS dropped significantly as the CO2 composition in the shielding gas increased beyond 25%. It decreased from 336 MPa at 70% argon-30% CO2 shielding gas composition to 133 MPa when 100% CO2 was utilized as the shielding gas. At the end, the effects of the CO2 addition and suitable composition of CO2 addition to argon shielding environment during GMAW of AISI 304 stainless steel have been established.

The weld joint is always the failure point in the arc welding of dissimilar metals due to microstructural heterogeneity. In this work, the microstructure and corrosion performance of gas metal arc weld (GMAW) joints between AISI 304 stainless steel (SS) and low carbon steel (LCS) were investigated under varying welding speed. ER309L wire electrode was used. The corrosion of the weld joints was investigated in de-aerated 3.5 wt.% NaCl solution. The microstructure of the weld joints which exhibited better grain refinement than the HAZ comprises of ferrite, retained austenite and delta-ferrite phases. The welding electrode compensated for Cr and Ni loss (due to dilution) in the weld joints. Cr and Ni composition in the weld joints are higher than the base metals and increased as the welding speed reduced. The corrosion performance of the weld joints was influenced positively as the welding speed decreased. The effects of the welding speed on the microstructure and corrosion performance of AISI 304 SS and LCS dissimilar GMAW has been determined.