Mechanical response of friction stir butt weld Al-4.5%Cu/TiB2/2.5p in situ composite: Statistical modelling and optimization

• Published in: Journal of alloys and compounds 2020-06, Vol.826, p.154184, Article 154184
• Main Authors: Mozammil, Shaik, Karloopia, Jimmy, Verma, Raviraj, Jha, P.K.
• Format: Article
• Language: English
• Subjects: Aluminum; Bimetals; Butt welding; Copper; Elongated structure; Friction stir welding; FSW; Grain structure; High resolution electron microscopy; HR-TEM; Joining; Mechanical analysis; Mechanical behaviour; Mechanical properties; Microhardness; Microscopy; Molecular composites; Optical properties; Optimization; Optimization techniques; Process parameters; RSM; Shoulder; Statistical model; Statistical models; Stir casting; Tensile strength; Titanium diboride; Welded joints
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.154184

The current investigation discusses the effectiveness of stir casting technique using the mixed salt route and friction stir butt welding (FSW) process for fabrication and joining of in situ Al-4.5%Cu/TiB2/2.5p composite, respectively. For joining the composite, a bimetallic flame hardened FSW tool with a threaded titanium probe having varying shoulder geometries was used. It was found that the variation in process parameters such as tool shoulder geometry, tool rotational speed, and welding speed influences the properties like tensile strength, percentage elongation, and micro-hardness of the welds significantly. The grain structure and dispersed reinforcement were refined and redistributed uniformly through Ti-weld probe during the FSW process. Microstructural evolution was studied through optical and scanning electron microscopy, which influences the mechanical properties a lot. The structure-property correlation was tandem with high resolution electron microscopy and X-Ray diffraction techniques. To predict the output responses of the joints, a statistical model was developed. Optimization technique based on multiple response desirability function was utilised to predict the target-optimized output responses. Through this model, it was determined that the tool was the most significant variable in the FSW of the aforementioned composite. In stir zone, there is an improvement of joint strength, percentage of elongation, and hardness varying from 18 to 64%, 40–280%, and 26–141%, respectively, as compared to base composite. •TEM results for attempting to explore in-depth mechanisms involved in AMC’s structure-property correlation.•Microstructural analysis of Al-4.5%Cu–TiB2/2.5p in situ composite.•Statistical modelling and Optimization of Al-4.5%Cu–TiB2/2.5p in situ composite.•Sensitivity analysis for finding most significant input process parameter of composite.