具有晶体学各向异性特征的DD5镍基单晶高温合金铣削力建模

Milling Force Modeling of DD5 Ni-based Single Crystal Superalloy with Crystallographic Anisotropic Characteristics

为了探究具有晶体学各向异性的DD5镍基单晶高温合金铣削力特征,基于分子动力学仿真、派纳力计算表达式、定向切割方法及槽铣实验,通过对单晶合金铣削变形机理的初步探索,对沿刀具进给方向的铣削力进行了定性建模,并对在(001)晶面上沿不同晶向方向进给铣削槽底表面质量进行了评价。研究结果表明,加工过程中切屑的形成是刀具对滑移面上层错的破坏和切屑原子沿滑移面攀升两种行为的综合,由于刀具前方大体积层错结构的破坏,加工进入稳定阶段。基于滑移系和有效分切应力理论,发现在(001)晶面上沿各晶向进给的铣削力均在18~27 N低水平区间内波动,铣削力、表面粗糙度、进刀轨迹间距和微观峰谷高度差均从[110]晶向向[470]、[100]和[740]、[010]两个晶向方向递增,因此,在DD5镍基单晶高温合金铣削加工过程中,沿[110]晶向的铣削加工可表现出最佳的铣削性能。

In order to research the milling force characteristics of DD5 Ni-based single crystal superalloy with crystallographic anisotropy,based on the molecular dynamics simulation,P-N force calculated expression,directional cutting method and slot milling experiments,and based on the preliminary exploration on single crystal alloy milling deformation mechanism,the milling forces along the feed direction of tools were qualitatively modeled,the slot bottom surface quality milled along the different crystal directions on the(001)crystal plane were evaluated.The research results show that the single crystal material removal is depended on the stacking fault structure destruction and chip atoms climb along the slip system,and the milling starts to enter into the stable processes when the bulk stacking fault structures are destoried.Based on the slip system and effective resolved shear stress theories,it is found that the milling force are fluctuated between the range of 18~27 N,the milling force,surface roughness,the adjacent tool feed track spacing and micro peak-valley height difference increase from the crystal direction[110]to[470],[100]and[740],[010].Therefore,during the milling processes of DD5 Ni-based single crystal superalloy,the milling along the[110]crystal direction may show the best performance.