Many difficult-to-cut materials such as Ni-base super alloy, titanium alloy, and austenite stainless steel which are used extensively in aerospace generally have high strength-to-weight ratios, high corrosion resistan...Many difficult-to-cut materials such as Ni-base super alloy, titanium alloy, and austenite stainless steel which are used extensively in aerospace generally have high strength-to-weight ratios, high corrosion resistance, high strength retention ability at elevated temperatures, and low thermal conductivity. These characteristics can result in uneven tool wear and chatter vibration. Therefore, determining the appropriate end-milling conditions is more difficult for difficult-to-cut materials than for other materials. There has been much research on the high-speed milling of difficult-to-cut materials, and effective end-milling conditions, end-mill tool shapes, and processing methods have been reported. In addition, irregular pitch and lead end-mills with different helix angles have been developed by tool maker＇s to reduce chatter vibration, making it easier to perform high-speed milling. However, there have been few reports of slotting information useful for determining appropriate end-milling conditions and processing methods for Ni-base super alloy. The aim of this study is to derive end-milling condition with high efficiency grooving process for Ni-base super alloy （Inconel 718） sheet. Effects of cutting parameters were examined from the view point of cutting resistance, ＂tool tip maximum temperature and tool flank wear width. As a result from experiments, if the grooving process condition of axial depth of cut is smaller than other conditions on the same material removable rate value, it has been found that it is possible to reduce the tool tip maximum temperature and prolong the tool life.展开更多
The chemical mechanical polishing(CMP)technology has been widely used for surface modification of critical materials and components with high quality and efficiency.In a typical CMP process,the mechanical properties o...The chemical mechanical polishing(CMP)technology has been widely used for surface modification of critical materials and components with high quality and efficiency.In a typical CMP process,the mechanical properties of abrasives play a vital role in obtaining the ultra-precision and damage-free surface of wafers for improvement of their performances.In this work,a series of fine structured rod-shaped silica(RmSiO2)-based abrasives with controllable sizes and diverse ordered mesoporous structures were synthesized via a soft template approach,and successfully applied in the sustainable polishing slurry for improving the surface quality of cadmium zinc telluride(CZT)wafers.Compared with commercial silica gel,solid and mesoporous silica spheres,the RmSiO2 abrasives present superior elastic deformation capacity and surface precision machinability on account of their mesoporous structures and rod shapes.Especially,ultra-precision surface roughness and relatively effective material removal speed were achieved by the CMP process using the RmSiO2 abrasives with a length/diameter(L/d)ratio of 1.In addition,a potential CMP mechanism of the developed polishing slurry to CZT wafer was elucidated by analyzing X-ray photoelectron spectra and other characterizations.The proposed interfacial chemical and mechanical effects will provide a new strategy for improving abrasives’machinability and precision manufacture of hard-to-machine materials.展开更多
文摘Many difficult-to-cut materials such as Ni-base super alloy, titanium alloy, and austenite stainless steel which are used extensively in aerospace generally have high strength-to-weight ratios, high corrosion resistance, high strength retention ability at elevated temperatures, and low thermal conductivity. These characteristics can result in uneven tool wear and chatter vibration. Therefore, determining the appropriate end-milling conditions is more difficult for difficult-to-cut materials than for other materials. There has been much research on the high-speed milling of difficult-to-cut materials, and effective end-milling conditions, end-mill tool shapes, and processing methods have been reported. In addition, irregular pitch and lead end-mills with different helix angles have been developed by tool maker＇s to reduce chatter vibration, making it easier to perform high-speed milling. However, there have been few reports of slotting information useful for determining appropriate end-milling conditions and processing methods for Ni-base super alloy. The aim of this study is to derive end-milling condition with high efficiency grooving process for Ni-base super alloy （Inconel 718） sheet. Effects of cutting parameters were examined from the view point of cutting resistance, ＂tool tip maximum temperature and tool flank wear width. As a result from experiments, if the grooving process condition of axial depth of cut is smaller than other conditions on the same material removable rate value, it has been found that it is possible to reduce the tool tip maximum temperature and prolong the tool life.
基金the National Key R&D Program of China(2018YFA0703400)the Xinghai Science Funds for Distinguished Young Scholars+1 种基金Thousand Youth Talents at Dalian University of Technology,the Collaborative Innovation Center of Major Machine Manufacturing in Liaoning,Liaoning BaiQianWan Talents ProgramDalian National Laboratory for Clean Energy(DNL),DNL Cooperation Fund,Chinese Academy of Sciences(DNL180402)。
文摘The chemical mechanical polishing(CMP)technology has been widely used for surface modification of critical materials and components with high quality and efficiency.In a typical CMP process,the mechanical properties of abrasives play a vital role in obtaining the ultra-precision and damage-free surface of wafers for improvement of their performances.In this work,a series of fine structured rod-shaped silica(RmSiO2)-based abrasives with controllable sizes and diverse ordered mesoporous structures were synthesized via a soft template approach,and successfully applied in the sustainable polishing slurry for improving the surface quality of cadmium zinc telluride(CZT)wafers.Compared with commercial silica gel,solid and mesoporous silica spheres,the RmSiO2 abrasives present superior elastic deformation capacity and surface precision machinability on account of their mesoporous structures and rod shapes.Especially,ultra-precision surface roughness and relatively effective material removal speed were achieved by the CMP process using the RmSiO2 abrasives with a length/diameter(L/d)ratio of 1.In addition,a potential CMP mechanism of the developed polishing slurry to CZT wafer was elucidated by analyzing X-ray photoelectron spectra and other characterizations.The proposed interfacial chemical and mechanical effects will provide a new strategy for improving abrasives’machinability and precision manufacture of hard-to-machine materials.
