Improvising of dissimilar friction stir weld strengths using biosilica nanoparticle: mechanical, fatigue and microstructure properties

The effect of introducing wheat husk biosilica (WHB) to the weld pool of different AA7075-AZ31B was investigated in this work. The biosilica particle of nano-dimensions was prepared from wheat husk wastes via thermo-chemical process. The prepared biosilica particles are again silane grafted for preventing clusters. The joints were made using a vertical machining centre with lap joint configuration. The properties such as tensile strength, yield strength, percent of elongation, hardness and fatigue strength were investigated in accordance to ASTM standards. Optical and SEM analyses were done to reveal the microstructural changes after the reinforcement addition. According to the findings, welds formed with WHB of about 1.0wt% had highest tensile strength of 326Mpa and fatigue strength of 152 MPa. It was discovered that the considerable amount of biosilica resulted in improved microhardness too. Because of the biosilica, the HAZ and TMT grains were refined and distortion free, which resulted improved mechanical and fatigue strength. Moreover, there are no particle agglomerations found. These property improved dissimilar welded joints could be deployed in aerospace, defence, automotive, oil & gas and shipping were stress free weld defects are required.

Automated summary

By introducing wheat husk biosilica into the weld pool of different materials, it was found that a biosilica content of about 1.0wt% had the highest tensile and fatigue strength. By optimizing the microstructure and improving the properties of the heat-affected zone and thermo-mechanically affected zone, the potential for enhancing mechanical and fatigue strength was provided.