不同挤压比对喷射成形7075铝合金后续工艺的影响

发布时间：2018-07-11 13:00

  本文选题：7075铝合金 + 挤压比　； 参考：《江苏理工学院》2015年硕士论文

【摘要】：喷射成形技术制备出的7075铝合金冶金质量相对较低,因此需要后续的形变处理及热处理来提高性能。该材料在挤压时,挤压比大小会对材料组织产生影响,而材料的组织影响着后续的热处理。因此,本文探索了挤压比大小对后续的热处理的影响,为实际生产提供理论依据。本论文主要采用金相、扫描电镜、X射线衍射及拉伸等测试手段分析了实验合金及热处理后实验合金的组织性能。研究结果主要如下:喷射成形坯经过不同挤压比挤压后,原始晶界消失。随着挤压比的增大,晶粒变形程度越大,合金的综合性能越好。但挤压比的变化导致了合金内部储存能不尽相同,反应在合金的再结晶程度。挤压比为8挤出的合金经固溶510℃×0.5h处理后,发生完全再结晶;挤压比为32挤出的合金经固溶460℃×2h处理后,发生完全再结晶;挤压比为60挤出的合金经固溶440℃×1h处理后,发生完全再结晶。随着挤压比的变化,与不同挤压比挤出的合金匹配的固溶温度与时间也发生了变化。与挤压比为8挤出的合金匹配的固溶处理工艺是490℃×1h;与挤压比为32挤出的合金匹配的固溶处理工艺是460℃×1h;与挤压比为60挤出的合金匹配的固溶处理工艺是435℃×1h。7075铝合金具有很强的时效析出强化效果,这适用于不同挤压比挤出的合金,单级时效中,不同挤压比挤出的合金在120℃×24h时,表现的性能最佳。挤压比为60挤出的合金由于固溶不充分,组织中残余第二相数量多、尺寸大,其性能不如其他挤压比下合金。双级时效中,终时效温度是影响强度、硬度的最大因素,预时效温度是影响伸长率的最大因素,不同挤压比合金经过双级时效后,与峰值时效相比,力学性能均有不同程度的下降。挤压比为8挤出的合金适宜的双级时效工艺是130℃×4h+150℃×12h;挤压比为32与60挤出的合金适宜的是130℃×3h+150℃×12h。
[Abstract]:The metallurgical quality of 7075 aluminum alloy prepared by spray forming technology is relatively low, so it is necessary to improve the properties of 7075 aluminum alloy by subsequent deformation and heat treatment. When the material is extruded, the extrusion ratio will affect the microstructure of the material, and the microstructure of the material will affect the subsequent heat treatment. Therefore, the effect of extrusion ratio on subsequent heat treatment is explored in this paper, which provides theoretical basis for practical production. In this paper, the microstructure and properties of the experimental alloy and the experimental alloy after heat treatment were analyzed by means of metallography, scanning electron microscope, X-ray diffraction and tensile test. The main results are as follows: the original grain boundary disappears after different extrusion ratio. With the increase of extrusion ratio, the higher the degree of grain deformation, the better the comprehensive properties of the alloy. However, the change of extrusion ratio leads to different internal storage energy, which is reflected in the recrystallization degree of the alloy. The alloy with extrusion ratio of 8 was treated with solution 510 鈩，

本文编号：2115278