Si、Sn元素对Cu-Ni-Sn-Si合金组织及性能的影响研究

发布时间：2018-06-19 21:30

本文选题：Cu-Ni-Sn-Si四元合金 + 显微组织结构　；参考：《江西理工大学》2017年硕士论文

【摘要】：近年来仪器设备都朝着小型化、高效能的趋势发展,这不仅要求电子元器件具备高集成度、飞快的信号传输速度,还要求其具备更高的性能。导电弹性铜合金材料以其突出的导热性、热稳定性及力学等性能而被普遍地用于电子通讯、仪表、弹性导电元件等领域中。其中,Cu-Ni-Sn系合金借助其优良的耐磨、耐腐蚀性能及良好的热稳定性等被用于生产制造各类弹性元件。但Cu-Ni-Sn系合金导电性能较差,其电导率通常在7%～8%IACS左右,且高Sn含量的Cu-Ni-Sn合金在凝固过程中容易出现严重的偏析现象而导致热轧开裂,这不仅会影响其加工成品率,同时也无法保证该合金制品性能的均匀性。基于此,本研究结合Cu-Ni-Sn、Cu-Ni-Si两系合金的特点,针对低Sn含量且添加少量Si以代替Sn的Cu-Ni-Sn-Si四元合金进行研究,系统研究了Si、Sn元素对Cu-Ni-Sn-Si合金组织及性能的影响规律,并探讨了常规形变时效、双冷轧双时效工艺对Cu-Ni-Sn-Si合金的影响,从而确定出较优的工艺参数,以期获得良好机械性能以及电导率的综合,并为实际生产提供良好的理论依据。主要研究工作及结果如下:(1)铸态Cu-Ni-Sn-Si合金组织中表现出明显的枝晶偏析现象,而且添加一定量的Si、Sn元素不仅可细化合金组织,改善偏析,同时对该合金硬度值与导电率产生的影响规律基本一致,即随着Si、Sn元素含量的增加,合金硬度值表现出持续增长的变化趋势,而其电导率逐渐下降,且在相同实验条件下Si元素对合金组织及性能影响作用更为显著;合金经预冷变形时效处理后,Sn原子仍完全固溶在Cu基体中,但是在相同时效条件下,添加的Si原子则容易与Ni形成Ni_2Si强化相,并在时效进程中迅速地从基体中析出,从而使合金强化,即合金硬度值与电导率均得到显著提高,且当Si为1%时,时效强化作用最为显著,但是当Si的含量大于1%时,反而会阻碍合金的时效进程。综合比较,合金较优的成分配比为:1%Si、1.5%Sn、4%Ni、余量为Cu。(2)Cu-4Ni-1.5Sn-Si合金经70%热轧后,再进行0%～70%预冷变形,在350℃～500℃、2h～8h条件下进行时效处理后发现:增大预冷变形程度、在350℃～450℃范围内升高温度均可促进合金时效进程,改善并提高其综合性能,且在6h时均达到硬度峰值,故综合比较得到合金较优的时效工艺为:70%预冷变形、450℃×6h,在该时效工艺下合金硬度及电导率分别达到269HB、26.6%IACS。(3)为了定量地分析在时效进程中合金预冷变形量对Ni_2Si相析出行为的影响关系,对预冷变形量为0%～70%,在450℃、保温2h～8h条件下时效的Cu-4Ni-1.5Sn-Si合金时效动力学进行了分析,并得到在时效过程中析出的Ni_2Si相体积分数f与合金预冷变形量ε的关系为:f=1-exp(?)(-0.030*t～(0.524+0.410ε)),由此可知,增大预冷变形程度,可以有效地促进Cu-4Ni-1.5Sn-Si合金时效析出进程,从而在理论上验证了适当增大预冷变形量可有效地提高合金导电性能,因此在Cu-4Ni-1.5Sn-Si合金实际生产过程中,在时效热处理前可以适当增大其预冷变形程度,有效改善时效析出过程及效果,为合金综合力学性能及导电性能的提高奠定良好基础。(4)为了进一步地改善合金综合性能,对30%、50%冷轧,500℃×2h预时效态Cu-4Ni-1.5Sn-Si合金进行70%二次冷轧后在375℃～450℃、保温6～8h的条件下进行二次时效处理发现:合金的较优双冷轧时效工艺为:50%冷轧、500℃×2h预时效、70%冷轧、400℃×8h二次时效,在该时效工艺下合金的硬度和电导率可分别达到275HB、33.2%%IACS,与常规的时效工艺(70%冷轧、450℃×6h)对比合金的硬度值及电导率都得到了一定程度的提高,尤其是合金电导率增大了24.8%。
[Abstract]:In recent years, the equipment has been developing towards miniaturization and high efficiency. It not only requires electronic components with high integration and fast signal transmission speed, but also requires higher performance. Conductive elastic copper alloy materials are widely used in electronic communication and instruments for their outstanding thermal conductivity, thermal stability and mechanical properties. In the fields of elastic conductive components, Cu-Ni-Sn alloys are used to produce various kinds of elastic components with their excellent wear resistance, corrosion resistance and good thermal stability. However, the electrical conductivity of Cu-Ni-Sn alloys is poor, the conductivity is usually about 7% to 8%IACS, and the Cu-Ni-Sn alloy with high Sn content is easy to produce during the solidification process. The serious segregation phenomenon causes hot rolling and cracking, which not only affects the rate of finished product, but also can not guarantee the uniformity of the properties of the alloy products. Based on this, this research combines the characteristics of Cu-Ni-Sn, Cu-Ni-Si two system alloys and studies the Cu-Ni-Sn-Si four element alloys with low Sn content and a small amount of Si instead of Sn. The influence of Si and Sn elements on the microstructure and properties of Cu-Ni-Sn-Si alloy, and the influence of conventional Deformation Aging, double cold rolling double aging process on Cu-Ni-Sn-Si alloy, are discussed, so as to determine the better technological parameters, in order to obtain good mechanical properties and the synthesis of electrical conductivity, and provide a good theoretical basis for practical production. The following work and the results are as follows: (1) the apparent dendrite segregation in the microstructure of the cast Cu-Ni-Sn-Si alloy, and the addition of a certain amount of Si, the Sn element can not only refine the alloy structure and improve the segregation, but also have the same effect on the hardness value of the alloy and the conductivity of the alloy, that is, with the increase of the content of Si, Sn element and the hardness value of the alloy. In the same experimental conditions, the effect of the Si element on the microstructure and properties of the alloy is more significant, and the Sn atom is still completely dissolved in the Cu matrix after the precooling deformation aging treatment, but the addition of Si atoms can easily form Ni_2Si with Ni under the same aging condition. Strengthening phase and precipitating rapidly from the matrix in the aging process make the alloy strengthen, that is, the hardness value and electrical conductivity of the alloy are greatly improved. When the Si is 1%, the aging hardening is the most significant. But when the content of Si is greater than 1%, it will hinder the time effect process of the alloy. 1.5%Sn, 4%Ni, the residual amount is Cu. (2) Cu-4Ni-1.5Sn-Si alloy after 70% hot rolling and then 0% ~ 70% pre cooling deformation. It is found under the condition of 350 ~ 500 C and 2H to 8h. It is found that increasing the pre cooling deformation degree and increasing the temperature in the range of 350 to 450 C can promote the aging process, improve and improve its comprehensive properties, and both in 6h. In order to reach the peak of hardness, the better aging process is: 70% pre cooling deformation, 450 x 6h, the alloy hardness and electrical conductivity are 269HB respectively, 26.6%IACS. (3) in order to quantitatively analyze the influence of the pre cooling deformation amount on the precipitation behavior of Ni_2Si phase during the aging process, and the pre cooling deformation amount is 0%. To 70%, the aging kinetics of Cu-4Ni-1.5Sn-Si alloy aging under the condition of 450 C and 2H ~ 8h was analyzed. The relation between the Ni_2Si phase integral number f and the pre cooling deformation quantity of the alloy during the aging process was f=1-exp (?) (-0.030*t ~ (0.524+0.410)). Thus, the increase of the pre cooling deformation degree could effectively promote the Cu-4. The aging precipitation process of Ni-1.5Sn-Si alloy proves that the proper increase of pre cooling deformation can effectively improve the conductive properties of the alloy. Therefore, in the actual production process of Cu-4Ni-1.5Sn-Si alloy, the pre cooling deformation degree can be increased properly before the aging heat treatment, and the process and effect of aging precipitation can be effectively improved and the alloy comprehensive force is improved. (4) in order to improve the overall performance of the alloy (4) to further improve the overall performance of the alloy, 30%, 50% cold rolled, 500 C 2H pre aged Cu-4Ni-1.5Sn-Si alloy after 70% two cold rolling at 375 to 450, and 6 to 8h under the condition of 6 to 8h, found that the superior double cold rolling aging process of the alloy is 50%. Cold rolling, 500 C 2H preaging, 70% cold rolling and 400 x 8h two times aging, the hardness and electrical conductivity of the alloy can reach 275HB, 33.2%%IACS respectively under the aging process, and the hardness and electrical conductivity of the alloy are improved by the conventional aging process (70% cold rolling, 450 C 6H), especially the electrical conductivity of the alloy increases 24.8%..
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG146.11

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