摘要
采用喷射沉积连续挤压方法制备7075铝合金以消除元素偏析、组织粗大、第二相分布不均和缩孔、缩松等缺陷,并将其微观组织和元素分布情况与铸态合金进行比较。研究表明,喷射沉积连续挤压7075铝合金杂质元素含量低、组织细小、合金元素分布均匀。金相组织观察表明喷射沉积使沉积坯平均晶粒尺寸比铸态合金显著减小,并呈等轴晶形态。经过连续挤压后,基体致密度提高,第二相细化,沿挤压方向均匀分布。TEM组织观察表明,沉积坯在连续挤压过程中发生动态再结晶,平均再结晶晶粒尺寸为3~5μm。回归再时效处理后屈服强度和伸长率达到493 MPa和12.6%,分别超过AMS 4050H航空标准的9.6%和26%。EDS分析结果表明,喷射沉积连续挤压制备的7075合金主元素偏析得到很好抑制,杂质元素O、C的分布更加均匀,有利于合金综合性能提升。
7075 aluminum alloy was prepared by spray deposition and continuous extrusion to eliminate the defects such as element segregation,coarse structure and uneven distribution of second phase and shrintage porosities and holes,and the microstructure and element distribution were compared with those of the as-cast alloy.The results indicate that the spray deposited and continuous extruded 7075 aluminum alloy has low content of impurity elements,fine microstructure and uniform distribution of alloying elements.The OM microstructure reveals that the average grain size of the deposited blank is significantly reduced compared with that of the casting alloy,presenting equiaxed crystal.After continuous extrusion,the matrix density is increased,and the second phase is refined and distributed uniformly along the extrusion direction.The TEM microstructure observes that the billets undergo dynamic recrystallization during continuous extrusion,and the average recrystallized grain size is 3~5μm.The yield strength and elongation of alloy after retrogression and re-aging treatment reach 493 MPa and 12.6%,which exceed 9.6%and 26%of the aviation standard AMS 4050 H limit,respectively.The EDS results demonstrate that the segregation of the main alloy elements prepared is well inhibited,and the impurity elements of oxygen and carbon are more evenly distributed,which is conducive to improving comprehensive properties of the alloy.
作者
陈业高
施允洋
张安民
尹建成
钟毅
Chen Yegao;Shi Yunyang;Zhang Anmin;Yin Jiancheng;Zhong Yi(School of Mechanical and Electrical Engineering,Suqian University;Faculty of Materials Science and Engineering,Kunming University of Science and Technology)
出处
《特种铸造及有色合金》
CAS
北大核心
2021年第12期1518-1524,共7页
Special Casting & Nonferrous Alloys
基金
国家自然科学基金资助项目(50874055,51864027)
宿迁市科技计划资助项目(K202003,Z2019111)
宿迁学院科技计划资助项目(2016KY07)
关键词
高合金化
喷射沉积连续挤压
7075铝合金
微观组织
High Alloying
Spray Deposition and Continuous Extrusion
7075 Aluminum Alloy
Microstructure
