(1. 北京航空航天大学 机械学院， 北京 100083；
2.成都飞机设计研究所， 成都 610041；
3. 成都飞机工业公司， 成都 610092)
摘 要: 为研究加工工艺对7075-T7351铝合金飞机装配紧固孔表面质量的影响，通过扫描电子显微镜和光学显微镜，分别对5种不同制孔工艺所产生的表面微观形貌和表层组织变化进行了观察和分析。结果表明，钻扩铰多步慢进给工艺和一步复合制孔工艺所加工出的表面，平整、光滑、加工缺陷少、晶格变形小、变质层薄；而其它工艺条件下，孔表面微观形貌复杂、加工纹路紊乱、表面缺陷多、晶格畸变大，变质层厚，这些加工状况，对紧固孔的装配性能和疲劳寿命都有很大的影响。
关键字: 铝合金；紧固孔；加工工艺；微观形貌；显微组织；加工缺陷
surface microphotograph and
microstructure of fastening holes
（1. Machinery College, Beijing University of
Aeronautics and Astronautics, Beijing 100083， P.R.China；
2. Chengdu Aircraft Design & Research Institute,
Chengdu 610041， P.R.China;
3. Chengdu Aircraft Industry Co. Chendu 610092， P.R.China）
Abstract: In order to study the effect of machining processes on the surface condition of fastening holes drilled on 7075 aluminum alloy for aircraft assembly, the surface microphotograph and surface layers microstructure produced by the five kinds of drilling processes were observed and analyzed by means of SEM and optical microscope. The results show that the surface microphotograph yielded in multiple-step machining with slow feeding and in one-step compound process is satisfactory, and there are fewer defects, lower deformation and thinner metamorphic layers; while that produced in other processes is quite rough, there are more defects and bigger deformation on the machined surface, and they are detrimental to assembly properties and fatigue life of fastening holes.
Key words: aluminum alloy; fastening hole; machining processes; microphotograph; microstructure; machining defect
