Experimental Research On Cutting Performance Of Titanium Alloys With Different Microstructure

Titanium alloys are found more and more applications in manyindustrial fields especially aerospace and aviation Industry, due to theirhigh specific strength, strong corrosion resistance and high thermalstability. However, titanium alloys are well known as hard-to-cuttingmaterials because of their characteristics such as high hardness, lowelastic modulus and low thermal conductivity and active chemicalreactivity. Accompanying with the development of modern industry,many new types of Titanium alloys are invented. As a result, how toimprove cutting performance, promote machining efficiency and reducecosts becomes a world-wide difficult problem.This paper studies the turning performance of different types of α+βTitanium alloys (TC4，TC6and TC11) with different micro-structuresfrom five aspects including cutting force, surface roughness, residualstress, tool wear and chips’ morphology.Based on the turning experiments, the study draw conclusion asfollows:1. Titanium alloys with different micro-structures have differentturning performance. TC4has the best cutting performance, followed byTC11and TC6the last.2. The cutting force coefficients and chip flow angle are revealed tohave no obvious relationship with cutting speed. Bigger cutting depth willdecrease the Chip flow angle when performing circular tool cutting.3. When cutting parameters are appropriately selected, good residualcompressive stress can be obtained after turning both TC6and TC11.4. When cutting parameters are appropriately selected, good surfaceroughness can be obtained when turning TC11.5. Tool wear is worse when turning TC6than TC11, and deformation degree of chip is higher.This paper also studies another three types of Titanium alloys (TC17,TC18and TA19) which have larger α to β proportion, we carry outresearch on milling performance from three aspects including cuttingforce, surface roughness and tool wear. Based on the milling experiments,the study draw conclusion as follows:1. In face milling process, among the three other kinds of titaniumalloys-TC17(an α+β titanium alloy with rich β-phase), TC18(Highalloying α+β titanium alloy) and TA19(near-α titanium alloy), titaniumalloy TA19shows the best cutting performance, followed by the TC18, andTC17the last. The poor machinability has limited cutting speed to less than110m/min when milling TC17and TC18.2. Compared with TC18, TA19has better surface roughness.3. According to the result of tool wear experiments, the main failureof cutter used in TC17’s milling is tipping, and when TC18is concerned,the primary failure mode of flank wear includes cohesive wear anddiffusion wear. and the failure mode of rake face wear is mainly craterwear. Much milder cohesive wear is found when milling TA19.