Volume 48, No 2, 2026, Pages 352-365
Download full text in PDFOptimizing Machinability and Surface Integrity of Aluminum Alloys 6061 Using Grey Relational Analysis in Turning Operations
Authors:
Abduljabar H. Ali 
,
Osamah F. Abdulateef ,
Wassan S. Abd Al-Sahb ,
Hiba K. Hussein ,
Basma L. Mahdi ,
Oday I. Abdullah 
DOI: 10.24874/ti.2123.01.26.04
Received: 30 January 2026
Revised: 12 March 2026
Accepted: 24 April 2026
Published: 15 June 2026
Abstract:
The study uses the grey relational analysis (GRA) to maximize the turning conditions of Aluminum Alloy 6061 (AA6061) to obtain an optimal compromise between roughness and hardness of the surface. Even though AA6061 is a high-strength material with a high level of corrosion resistance, the highest machinability is not easily attained. A Taguchi L27 orthogonal array was used to explore the interactive effects of cutting speed, feed rate, and depth of cut. The best parameter combination that was determined through GRA was a cutting speed of 230 m/min, a feed rate of 0.07 mm/rev, and a depth of cut of 0.2 mm, which gave the best Grey Relational Grade of 0.8067 (Experiment 10). The surface finish of 0.53 µm and the hardness of 75.73 HV were excellent. The hypothesis that feed rate has the most significant variable influence on machining outcomes was tested using ANOVA. The outcomes of the ANOVA proved the dominance of feed rate, which has 42.3% contribution to the Grey Relational Grade (p = 0.001), depth of cut (20.6%, p = 0.017), and cutting speed (7.2%, p = 0.21). The remaining error explained 29.9 percent of the overall variation, implying that other variables, including interactions of parameters, wear development of tools or even variability of materials, might affect the performance of multi-objective machining. In contrast to the earlier GRA-based research on AA6061 that dealt with the isolated parameter effects, this study is the first to measure parameter interaction dynamics and provides a statistically rigorous baseline with error contribution analysis (29.9%), as well as an established benchmark of future integration of sustainable cooling strategies.
Keywords:
Surface engineering, Grey relational analysis, Aluminum alloy 6061, Machining parameters, Turning operation, Surface roughness, Hardness
