周期性载荷对超精密加工中磷锗锌晶体力学特性的影响  

Influence of cyclical loading on mechanical properties of ZGP crystals in ultra-precision machining

作　　者：徐康 段没方 李东亚 姜志伟 刘禹 XU Kang;DUAN Fang;LI Dongya;JIANG Zhiwei;LIU Yu(School of Mechanical Engineering,Jiangnan University,Wuxi 214122,China;Institute of Mechanical Manufacturing Technology,China Academy of Engineering Physics,Mianyang 621900,China)

机构地区：[1]江南大学机械工程学院,江苏无锡214122 [2]中国工程物理研究院机械制造工艺研究所,四川绵阳621900

出　　处：《材料科学与工艺》2025年第2期19-26,共8页Materials Science and Technology

基　　金：四川省科技计划资助(2023NSFSC0852).

摘　　要：磷锗锌(ZGP)是一种综合性能优异的非线性中红外光学硬脆晶体材料,为了获得高质量的加工表面,需要研究其在循环接触载荷下的力学特性变化。本文首先采用纳米压痕实验研究了ZGP晶体在单/周期载荷-卸载下的机械力学特性变化,并依据该力学特性结果指导加工参数,在五轴单点金刚石机床上进行了加工实验,利用白光干涉仪分析了样件的表面加工质量。纳米压痕实验结果表明:ZGP晶体在周期载荷下的显微硬度比单载荷提高了约4%,弹性模量提高了约6%,临界载荷提高了约6%;同时根据结果分析可得ZGP晶体的断裂韧度提高了约15%,同时脆塑转变临界切削深度提高了约27%。此外,载荷-位移曲线表明,ZGP晶体在周期载荷下,随着实验载荷的增大后续加载周期在最大载荷下的位移会逐渐右移,即出现增大现象。在临界断裂载荷附近材料发生了突起(Pop-in),即发生了断裂,同时出现弯头(Elbow),即发生了弹性恢复和体积膨胀现象。依据纳米压痕实验得出的临界切削深度参数,进行超精密加工实验,获得了粗糙度Ra为0.5039 nm,Sa为2.368 nm的超光滑表面。周期循环载荷可以提高ZGP晶体的部分力学性能,在周期动态加工中应予以考虑。ZGP is a nonlinear mid-infrared optically hard and brittle crystalline material with excellent comprehensive properties.In order to obtain high-quality machined surfaces,it is essential to investigate the changes of its mechanical properties under cyclic contact loading.In this paper,the mechanical property changes of ZGP crystals under single/cyclic loading-unloading were investigated using nanoindentation experiments.Based on the results of this mechanical property,the machining experiments were conducted on a five-axis single-point diamond machine tool,guided the machining parameter,The surface machining quality of the sample parts was analyzed using a white light interferometry to access the quality of the machining process.The results of the nanoindentation experiments show that the microhardness of the ZGP crystals under cyclic loading increases by approximately 4%compared to single loading,while the modulus of elasticity and critical load increase by approximately 6%.Additionally,the fracture toughness of ZGP crystals increases by approximately 15%,and the critical depth of cut for brittle-plastic transition increases by approximately 27%.In addition,the load-displacement curves show that under periodic loading,as the experimental load increases,the displacement of ZGP crystals at the maximum load gradually shift to the right side,indicating an increase in displacement.In the vicinity of the critical fracture load,a pop-in occurs,indicating fracture along with the occurrence of an elbow,showing elastic recovery and volume expansion.Based on the critical cutting depth parameter obtained from the nanoindentation experiments,ultra-precision machining experiments were carried out to obtain ultra-smooth surfaces with roughness Ra of 0.5039 nm and Sa of 2.368 nm.The results demonstrate that periodic cyclic loading can improve certain mechanical properties of ZGP crystals.Therefore,the consideration of periodic dynamic loading should be taking into account in the context of cyclic dynamic machining.

关 键 词：磷锗锌晶体 周期载荷 纳米压痕 力学特性 超精密加工 

分 类 号：TB301[一般工业技术—材料科学与工程]