Manufacturing Methods Induced Property Variations in Ti6Al4V Using High-Speed Machining and Additive Manufacturing (AM)

Abstract

Additive manufacturing techniques are replacing conventional subtractive machining processes; however, the surface quality and defects have been a key roadblock to expanding AM’s uses. This paper describes experimental investigations in the high-speed dry machining and additive manufacturing (AM) of titanium alloy (Ti6Al4V), discussing the effect of machining and AM conditions on the surface characteristics due to the micro-deformation layer. Analysis of the machined surfaces shows the deposition of microparticles at a high cutting speed of 170 m/min at moderate feed rates. The predominant thermal softening effect at a high cutting speed causes restructuring of the micro-deformation layer. Thus, the machined surface shows fewer alterations and a correspondingly lower surface roughness. A high cutting speed also favors the induction of high residual stresses that are compressive. Shallow grooves are seen throughout the surface along the feed spacing with a higher depth of cut of 0.8 mm. An increase in the cutting speed from 170 m/min to 190 m/min leads to a 61% increase in the surface finish owing to a rise in machining temperature leading to thermal softening, and subsequent restructuring of the machined surface layer occurs. For the feed rate, the surface finish values decrease gradually as the feed rate increases, and the worst finish of 1.37 µm is attained at a feed rate of 0.875 mm/rev. This study also compares different AM processes for Ti6Al4V based on the defects and their effects on mechanical properties, such as tensile and fatigue strength. It was observed that the ultimate tensile strength and the yield strength were approximately 20% more in SLM and direct energy deposition as compared to electron beam melting. The mechanism of these effects is also explained by elaborating on the influence of grain size, phase, and other microstructural behaviors on the final mechanical properties of the produced part.

A Review on Vibration Characteristics of Additively Manufactured Metal Alloys

“…[94] The geometry of AM-fabricated metal alloys significantly influences the vibrational and damping performance. [95,96] The AM technology helps to fabricate complex geometries, such as cellular or LSs. The LSs are naturally inspired structures formed by repeating the fundamental building block known as the unit cell.…”

Optimization of Sustainable Production Processes in C45 Steel Machining Using a Confocal Chromatic Sensor

“…Investigations into factors affecting the machined surface of metallic materials are carried out by the authors of [37,38]. The authors of [39] observe the deterioration of machined surfaces in Ti6Al4V alloys due to thermal softening using the HSM method. Similarly, results from [40] indicate a trade-off relationship between significant process factors' influence on material removal rate and surface roughness.…”

Multi-Response Optimization of Additively Manufactured Ti6Al4V Component Using Grey Relational Analysis Coupled with Entropy Weights

“…The Ti6Al4V samples exhibited greater machinability with lower cutting forces and lower surface roughness due to the material's rapid cooling. Yadav and Pawade [16] evaluated the compatibility and property variations of Ti6Al4V produced using AM methods (e.g., EBM, SLM, and direct energy deposition (DED)) to those produced via traditional manufacturing. According to the findings, the feed rate and the depth of cut are the most important factors in determining the presence and severity of defects (such as shallow grooves, micro-particle deposits, white layers, etc.)…”