Experimental Study on the Comparison between Network Microstructure Titanium Matrix Composites and Ti6Al4V on EDM Milling

• Published in: Materials Vol. 17; no. 10; p. 2282
• Main Authors: Zhang, Leheng, Hu, Yizhou, Gong, Sirui, Wang, Zhenlong
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01-05-2024
• Subjects: Aluminum; Analysis; Composite materials; Density; Ductility; EDM milling; Electric discharge machining; Electrolytes; Experiments; Hot pressing; Liquid metals; Melting points; Metal matrix composites; Microcracks; Microstructure; Milling (machining); Morphology; NMTMCs; Physical properties; recast layer thickness; recast layer thickness range; Reinforcement; Surface properties; Surface roughness; Temperature; Thermal conductivity; Thickness; Ti6Al4V; Titanium; Titanium alloys; Titanium base alloys; Whiskers (metals); Workpieces; surface microcrack density; NMTMCs; recast layer thickness range; recast layer thickness; EDM milling; Ti6Al4V; surface roughness
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17102282

Network microstructure titanium matrix composites (NMTMCs), featuring Ti6Al4V as the matrix and network-distributed TiB whiskers (TiBw) as reinforcement, exhibit remarkable potential for diverse applications due to their superior physical properties. Due to the difficulty in machining titanium matrix composites, electrical discharge machining (EDM) stands as one of the preferred machining techniques for NMTMCs. Nevertheless, the compromised surface quality and the recast layer significantly impact the performance of the workpiece machined by EDM. Therefore, for the purpose of enhancing the surface quality and restraining the defects of NMTMCs, this study conducted comparative EDM milling experiments between NMTMCs and Ti6Al4V to analyze the effects of discharge capacitance, charging current, and pulse interval on the surface roughness, recast layer thickness, recast layer uniformity, and surface microcrack density of both materials. The results indicated that machining energy significantly influences workpiece surface quality. Furthermore, comparative experiments exploring the influence of network reinforcement on EDM milling revealed that NMTMCs have a higher melting point, leading to an accumulation phenomenon in low-energy machining where the reinforcement could not be completely removed. The residual reinforcement in the recasting layer had an adsorption effect on molten metal affecting the thermal conductivity and uniformity within the recasting layer. Finally, specific guidelines are put forward for optimizing the material's surface roughness, recast layer thickness, and uniformity, along with minimizing microcrack density, which attain a processing effect that features a roughness of Ra 0.9 μm, an average recast layer thickness of 6 μm with a range of 8 μm, and a surface microcrack density of 0.08 μm
.