This study examines the effects of cutting parameters on surface roughness (Ra) for three aluminum alloys AL7075, AL6061, and AL5052 using a Taguchi L16 (43) design, smaller-is-better signal-to-noise (S/N) analysis, and ANOVA. Experiments were conducted on a 3-axis CNC milling machine with a 2-flute & Oslash;6 mm carbide end mill. Overall, AL7075 produced the smoothest surface (minimum Ra = 0.143 mu m), followed by AL6061 and AL5052. The observed trends are consistent with machining mechanics: increasing cutting speed suppresses built-up edge (BUE) and vibration, whereas larger feed and depth of cut (doc) increase chip load and tool deflection. For AL7075, doc and feed were the principal factors (borderline significant in S/N-ANOVA); the mean-optimal setting was S3-F1-D3 = Spindle L3 (N = 2500 rpm), Feed L1 (f = 150 mm.min(-1)), doc L3 (0.8 mm), while the robust-optimal setting was S4-F1-D3 = Spindle L4 (N = 3500 rpm), Feed L1 (f = 150 mm.min-(-1)), doc L3 (0.8 mm). For AL6061, spindle speed was strongly dominant (approximate to 80.5% contribution; p < 0.001), with S3-F1-D1 = 2500 rpm, 150 mm.min(-1), 0.4 mm as the mean optimal and S3-F1-D2 = 2500 rpm, 150 mm.min(-1), 0.6 mm as the robust-optimal combination. For AL5052, factor contributions were relatively balanced and not significant at alpha = 0.05; the mean optimal setting was S4-F2-D3 = 3500 rpm, 250 mm.min(-1), 0.8 mm, whereas S/N indicated S1-F4-D4 = 500 rpm, 450 mm.min(-1), 1.0 mm (requiring confirmation tests). Across alloys, doc and spindle speed emerged as the most practically influential factors. These results establish ANOVA validated mean and robust (S/N) settings as process guidelines to minimize Ra; confirmation tests are recommended.
This work investigates atmospheric plasma spraying (APS) coatings on aluminum molds used for truck tire vulcanization. Cobalt-based powders (MS1) and a NiAl interlayer combined with cobalt powders (MS1 + MS2) were deposited on AlMg3Mn alloy substrates. SEM/EDS analyses revealed that the NiAl interlayer improved adhesion, reduced chromium agglomeration, and enhanced elemental homogeneity. Vickers microhardness testing showed higher hardness values for MS1 + MS2 (457 HV 0.3) compared to MS1 (436 HV 0.3). Despite some residual cracks and porosity, their impact on performance was minimal. The study concludes that NiAl interlayer coatings significantly improve mold durability and operational life. Automated application and controlled-atmosphere spraying methods are recommended to further optimize coating properties for industrial use.
The study analyses current trends in the manufacturing of highly stressed components used in the defence industry, with a particular focus on handgun components. These parts are commonly produced from low-alloy steels that are refined to achieve medium strength levels. To enhance their resistance to mechanical and thermal loading, conventional production routes typically involve surface hardening followed by tempering. This study investigates the potential of replacing these established methods with a chemical-thermal surface treatment, specifically boriding, in which the surface layer is enriched with boron atoms. The mechanical properties of selected materials used for test samples are described and compared after treatment by induction surface hardening and boriding. The results provide a basis for evaluating the applicability of boriding as an alternative surface treatment for highly stressed components in the defence industry.
Additive manufacturing (AM), more commonly known as 3D printing, is a highly convenient manufacturing process that enables the creation of complex 3D objects. The large body of literature proved that the choice of material, the printing technology used, and the values of certain process parameters all influence the mechanical behavior of the final part. In this study, the Fused Deposition Modeling (FDM) technology was used to manufacture standardized test specimens, which were all subjected to mechanical testing. The main aim of the research was to investigate the effects of various infill patterns, combined with various infill densities, on tensile strength, and thus determine the patterns that enhance better structural performance. Three infill density levels were analyzed along with five infill patterns. A systematic sequence of tensile tests traced the correlation between internal material distribution and measured mechanical properties. By systematically varying the infill parameters, this study provides valuable insights into selecting appropriate configurations for specific applications. The findings contribute to advancements in AM design and material utilization, leading to stronger and more efficient components.
The presented article deals with the influence of different solution annealing temperatures and times on the mechanical properties and microstructural changes of the EN AW-7022 aluminum alloy after two-stage re-aging. Following initial soft annealing, the specimens underwent solution treatment at 475 degrees C/ 20 min, 500 degrees C/20 min, 525 degrees C/30 min and 575 degrees C/30 min, followed by two-stage artificial aging at 120 degrees C/4 h and 175 degrees C/6 h. Mechanical properties were assessed using static tensile testing and Vickers hardness measurements. The highest strength levels were achieved after treatment at 525 degrees C/30 min. Metallographic observations together with SEM-EDS microanalysis confirmed a uniform distribution of strengthening precipitates of the Al2CuMg and Mg(Zn,Cu,Al)2 types at elevated temperatures, while fractographic examination indicated a predominantly ductile fracture mechanism. The results demonstrate that, even in the absence of additional plastic deformation, an advantageous combination of strength, hardness and ductility can be obtained through re-heat treatment. This is particularly beneficial for applications where dimensional stability and minimized residual stresses are required, such as in defense and aerospace components.
