热挤压及热处理工艺对2A14铝合金组织及性能的影响

发布时间：2018-07-08 10:01

  本文选题：2A14铝合金 + 挤压比　； 参考：《哈尔滨理工大学》2017年硕士论文

【摘要】：本文通过热挤压实验、热处理实验、金相显微组织观察、扫描(SEM)显微组织观察、能谱分析、透射(TEM)电镜观察、力学性能测试等方法对2A14铝合金进行研究。研究了不同挤压比下合金组织及力学性能的变化以及热处理制度对合金组织及性能产生的影响。实验结果表明,热挤压过程中合金组织发生动态再结晶,合金内位错密度较低;热挤压对合金的强化作用是形变强化与动态再结晶共同作用的结果,第二相通过钉扎位错和晶界来延缓动态再结晶速度;随着挤压比的增大,合金组织呈现均匀分布,第二相颗粒也随之均匀分布且尺寸更加细小,形变强化作用增强,对材料的力学性能提升效果明显;挤压态的2A14铝合金的主要强化相为 θ(Al_2Cu)、Mg_2Si 以及 ω(Cu_4Mg_5Si_4Alx),主要的杂质相为(FeMnSi)Al_6 或(FeMn)Al_6;热处理工艺中四个影响因素对合金抗拉强度的影响效果从大到小依次为:时效时间、固溶温度、时效温度、固溶时间,研究发现固溶温度越高,第二相颗粒溶入基体的比例越大,对后续的时效强化提供了有利条件;时效处理后,Cu元素大量析出,Mg元素含量也有所增加,在合金基体上形成θ相与S(Al_2CuMg)相,并可能含有少量ω相。这些强化相分布十分均匀且尺寸细小,对合金强化起重要作用。实验证明:在挤压比为36:1的条件下,材料经过505 ℃×1.5 h固溶处理、30℃-50℃水淬、160℃×8 h时效处理后,材料的抗拉强度和伸长率分别达到 352.7 MPa 和 15.3%。
[Abstract]:In this paper, 2A14 aluminum alloy was studied by means of hot extrusion, heat treatment, metallography, scanning, energy dispersive analysis, transmission electron microscope and mechanical properties. The microstructure and mechanical properties of the alloy under different extrusion ratios and the effect of heat treatment on the microstructure and properties of the alloy were studied. The experimental results show that dynamic recrystallization occurs in the microstructure of the alloy during hot extrusion, and the dislocation density in the alloy is low, and the strengthening effect of hot extrusion on the alloy is the result of both deformation strengthening and dynamic recrystallization. The second phase delays the dynamic recrystallization rate by pinning dislocations and grain boundaries. With the increase of extrusion ratio, the microstructure of the alloy is uniformly distributed, and the second phase particles are uniformly distributed and the size of the second phase particles is smaller, and the deformation strengthening effect is enhanced. The main strengthening phases of extruded 2A14 aluminum alloy are 胃 (Al2Cu) Mg2Si and 蠅 (Cu4Mg5Si4Alx), the main impurity phases are (FeMnSi) Al_6 or (FeMn) Al6.The effects of four factors on the tensile strength of the alloy are as follows: aging time, solid solution temperature, It was found that the higher the solution temperature, the higher the proportion of the second phase particles dissolved into the matrix, which provided favorable conditions for the subsequent aging strengthening. 胃 phase and S (Al2CuMg) phase are formed on the alloy matrix and may contain a small amount of 蠅 phase. These strengthening phases are uniformly distributed and small in size, and play an important role in strengthening the alloy. The results show that when the extrusion ratio is 36:1, the tensile strength and elongation of the material can reach 352.7 MPA and 15.3 MPA respectively after 30 鈩，

本文编号：2107064