Nanoparticle induced control (MWCNTs-TiO2) on grain size and tensile strength response and multi response optimization on TIG welded joints

The presented study has discussed the effectual variable parameters declaring multi-walled carbon nanotubes and titanium oxide (MWCNTs-TiO2) contents, and welding current in obtaining the response on mechanical behavior. The experimental work involved three levels of both the parameters, which include 1wt%, 1.5wt%, 2wt% of MWCNTs-TiO2, and 160A, 180A, 200A of current by forming a full design representing 32 (3k) factorial model. The results of the analysis of variance (ANOVA) have been critically employed to assess the variation between the variables and within their levels for approaching the significant combination of parameters. The joints welded with MWCNTs-TiO2 coated fillers tendered a significant reduction in grain size (GS) along with high values of the tensile strength (TS). From ANOVA, it was determined that both the investigated parameters and their combined effect have created a significant response for GS reduction and increment in TS. The presented empirical regression quadratic model is validated for the adequacy of the projected results that were shown acceptable with the experimental investigated data. In addition, the desirability function approach is applied for the multiple response optimization (MRO) in yielding the desired responses of GS and TS with simultaneously providing the optimized set of process parameters. Thus, the function declared 1.5wt% MWCNTs-TiO2 and 180A as the optimized process set for delivering the maximum TS at the designated range of GS for this system.