| Ti40alloy is a new burn resistant titanium alloy designed for aeroengine in case normal titaniumcomponents will burn under hot environment. It’s one kind of beta titanium alloys, offering higherspecific strength, better properties under high temperature and excellent burn resistant performance.However, the favorable mechanical capabilities leads to challenges in machining operations mainlyreflect in the rapidly increasing tool wear which strictly decreases cutting efficiency. In view of this,applying Cryogenic Pneumatic Mist Jet Impinging (CPMJI) cooling method and coated carbide tools,the machinability of titanium alloy Ti40is studied in milling process, expecting to offer theoreticalevidence and basical information to solve problems arising in cutting of Ti40.The main contents are as follows:(1) Cutting force and temperature in milling of Ti40is measured under different coolingconditions. The results indicate that, when the cutting speed ranges in30-100m/min, compared to coldair and conventional flood cooling, CPMJI has better effect on cooling and lubricating because of thesufficient atomization of coolant and high-speed jet impingement, which expand heat exchange areaand make more coolant enter the cutting area.(2) Life of coated carbide tools in milling of Ti40is investigated, and the surface roughness isstudied. The longest tool life and lowest surface roughness is gained under CPMJL condition becauseof the decrease of cutting force and temperature.(3) Tool wear feature and wear mechanism of coated carbide tools in milling of Ti40is observed.The three-dimensional video microscope, SEM and EDS are utilized. The results show that, the mainwear feature are peeling of coating and tool matrix, boundary wear and tipping. Abrasive wear,adhesion wear and diffusion wear are the main wear mechanisms in milling of Ti40. |
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