Research On Preparation Technology Of High-Performance Film On The Surface Of Drilling Tools For CFRP/Ti Laminated Structure

Carbon fiber reinforced polymer(CFRP)and titanium alloys are widely used in the aerospace field,resulting in a large number of connection and assembly requirements between the two parts.Both CFRP and titanium alloys are typical difficult-to-machine materials,which make the process of drilling CFRP/Ti alloys laminar structure problems such as short drill life,poor hole quality,and low processing efficiency.Diamond like carbon(DLC)films show excellent characteristics such as wear resistance,corrosion resistance and self-lubrication,and it is expected to become an ideal film material to solve the problem of CFRP/Ti laminar structure during the hole making.This study is aimed to the study on the preparation of high performance DLC films on the surface of cemented carbide specimens and drill tools,respectively.And comprehensive performance analysis and optimization were carried out.Wet sandblasting and drag grinding(polishing)are also used for rounding the cutting edge of cemented carbide drilling tools,and then the preferred film was prepared on the edge.The high performance DLC film deposited on drilling tools,which is suitable for CFRP/Ti laminar structure drilling and its preparation process were obtained.The main research contents and conclusions of this study are as follows:The W-DLC film with CrN,TiAlN and CrAlN as the transition layer was designed,and CrN+W-DLC,TiAlN+W-DLC,CrAlN+W-DLC were prepared on the surface of the cemented carbide samples by using a multifunctional ion plating deposition system,respectively.Through the performance comparison of W-DLC films with different transition layers,it was found that the bonding force of the CrN+W-DLC film is the highest,which reaches 58.10N,and the adhesion shows best performance,which is HF1;W-DLC films with different three transition layers all showed good tribological behavior under the loading of 2N;CrN+W-DLC films showed the best impact toughness.In order to evaluate the drilling performance of W-DLC films with different transition layers,the above-mentioned W-DLC films were prepared on the surface of cemented carbide drilling tools,and drilling tests were carried out on the CFRP/Ti alloys laminar structure.After 31 holes were drilled under the same test conditions,the wear on the main back of the CrN+W-DLC coated drill tool was 61.7?m,and the one-dimensional layering coefficient Fd of the CFRP export was 1.11,which is better than the other two films deposited on drilling tools and cemented carbide drilling tools without films.Wet sandblasting and drag grinding(polishing)are used for rounding the cutting edge of cemented carbide drilling tools,respectively.And to deposit CrN+W-DLC film on the cutting edge,then to carry out the driling performance comparison with unpassivated film drilling tools.The results show that the CrN+W-DLC coated drills with wet sandblasting and drag grinding(polishing)for cutting edge rounding have better drilling performance than the CrN+W-DLC coated drills without cutting edge passivation;and the CrN+W-DLC coated drill with wet sandblasting for edge passivation has the best drilling performance.When the same number of holes were drilled,the hole quality of titanium alloy and CFRP is the best.In summary,the cutting edge rounding of cemented carbide drilling tools and the preparation of high-performance DLC films on the surface can effectively improve the hole processing quality and drilling tool life of CFRP/Ti alloys laminar structure,and it is of great significance to improve the safety and reliability of the two material structures assembly.