Investigation on Morphological Evolution of Chips for Ti6Al4V Alloys with the Increasing Milling Speed

Titanium alloy, one kind of typically difficult-to-cut materials, is widely used as structural parts in aerospace industry. In this study, orthogonal milling, an experimental way based on Buda's method to realize orthogonal cutting by milling and different from conventional method to realize high cutting speed for difficult-to-cut materials like ballistic impact, is adopted to reach the cutting speed ranging from 50-500m/min for Ti6Al4 V alloy. Cutting forces and cutting temperatures are both measured, and the obtained chips are analyzed by metallurgical treatments. The results show that the serrated degree(Gs) of chips increases first and then decreases with the elevating cutting speed, and continuous-to-serrated transition occurs in one single chip, which is different from the regular rules that Gs remains increasing with elevating cutting speed. But the measured cutting forces and temperatures show the same variation as serrated phenomenon, it may be concluded that cutting forces and temperatures are the critical factors in morphological evolution of chips.