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The effect of machining on surface integrity of gamma titanium aluminides using different cemented carbide tools

Abstract:

Gamma titanium aluminides are a new generation of light materials that compete with nickel or cobalt superalloys, when it comes to the manufacture of very high resistance requirement components such as low and high-pressure compressor blades, in the case of aeronautical applications. Machining is a process used to manufacture such components. However, in available literature, the specific information regarding machining performance of gamma titanium aluminides is scarce. The present research focused on the comparative study of the performance of coated tungsten carbide (WC-Co) inserts with round geometry in face milling operation of a gamma titanium aluminide alloy (Ti-48Al-2Nb-0.7Cr-0.3Si). Six different cutting-inserts in a combination of three different compositions of WC-Co substrates and two edge-geometries (XL and XM) recommended for conventional titanium alloys were tested. Milling experiments were carried out for different cutting speed, depth of cut and chip thickness. The results are discussed in terms of the correlation between cutting parameters with cutting force, surface roughness and work-hardening. The study showed that chip thickness, significantly affected the machined surface integrity in related with the tool insert geometry. Insert type C-XL showed better performance for cutting speed to 45 m/min, while inserts types A-XL and B-XM showed better behavior for cutting speed to 70 m/min.