摘要
利用真空热压烧结制备了Si_(3)N_(4)颗粒增强铝基复合材料,进而基于分流共挤方法,分别实现了Si_(3)N_(4)/Al复合材料与1060、6063和7A99铝合金的连接。研究了异种金属型材的焊合界面、晶粒形貌和微观织构,明确了挤压温度和微观组织对力学性能的影响规律。结果表明:Si_(3)N_(4)/Al复合材料与铝合金的连接界面处无裂纹、孔洞和杂质等缺陷,焊合质量良好。Si_(3)N_(4)/Al复合材料在挤压过程中发生了部分动态再结晶,表现为拉长的条状晶粒和细小等轴晶,再结晶分数和晶粒尺寸随挤压温度的升高均有所增大。Si_(3)N_(4)颗粒的引入导致了粒子激发形核机制,也促进了动态再结晶的发生。不同铝合金经过挤压后的晶粒形貌差别明显,随着挤压温度的升高,1060和7A99铝合金发生了较为完全的动态再结晶,而6063铝合金则发生了晶粒异常长大。此外,异种金属型材中普遍存在强度较高的轧制织构以及一些强度较弱的再结晶织构。Si_(3)N_(4)/Al与7A99铝合金连接时,极限抗拉强度最高,但伸长率最低,而与1060铝合金连接时则表现出相反趋势。
The Si_(3)N_(4)particle reinforced Al based composite is fabricated by vacuum hot pressing sintering,and the Si_(3)N_(4)/Al composite is respectively joined with 1060,6063 and 7A99 aluminum alloys based on porthole die co-extrusion method.The bonding interface,grain morphology and micro-texture of the profile with dissimilar alloys,and the effects of extrusion temperature and microstructure on the mechanical properties are clarified.The results show that no crack,void and impurity exist on the bonding interface between Si_(3)N_(4)/Al composite and aluminum alloys,which indicates a favorable bonding quality.The partial dynamic recrystallization takes place in Si_(3)N_(4)/Al composite during extrusion process,exhibiting as elongated and strip-shaped grains as well as fine equiaxed grains,and both the recrystallization fraction and grain size increase with the increase of extrusion temperature.Moreover,the dynamic recrystallization is also enhanced,since the particle stimulated nucleation is promoted due to the addition of Si_(3)N_(4)particles.The grain morphology exhibits obvious differences in different aluminum alloys.With the increase of extrusion temperature,the near complete dynamic recrystallization occurs in 1060 and 7A99 aluminum alloys,while the abnormal grain growth takes place in 6063 aluminum alloy.In addition,it is noted that the relatively strong rolling texture and some weak recrystallization textures are found in the profile with dissimilar alloys.When Si_(3)N_(4)/Al is joined with 7A99 aluminum alloy,the highest ultimate tensile strength and lowest elongation are achieved,while an opposite tendency is observed when Si_(3)N_(4)/Al is joined with 1060aluminum alloy.
作者
王辉
陈良
李志刚
赵国群
张存生
WANG Hui;CHEN Liang;LI Zhigang;ZHAO Guoqun;ZHANG Cunsheng(Key Laboratory of Liquid-Solid Structure Evolution and Materials Processing(Ministry of Education),Shandong University,Jinan 250061)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2022年第16期89-99,共11页
Journal of Mechanical Engineering
基金
国家自然科学基金(52175338)
山东省杰出青年基金(ZR2021JQ21)
山东省重点研发计划(2021ZLGX01)资助项目
