熔体结构转变对耐磨合金凝固行为及组织影响

发布时间：2018-04-18 08:43

本文选题：耐磨轴承合金 + 铝青铜　；参考：《安徽工程大学》2015年硕士论文

【摘要】：合金的凝固行为及组织性能都与合金熔体结构有着密切的关系。当前,合金化、快速凝固法和形变热处理等方法是合金组织性能改善的主要方法,而采用熔体过热处理工艺诱导合金熔体的结构发生改变,进而改善合金的凝固过程、凝固组织和性能仍然是经验性的。本文以三种典型的耐磨工业合金(SnSb11Cu6、Al-20Sn、QAl10-44)为研究对象,通过熔体电阻率的变化研究熔体结构的变化规律,从而对合金进行熔体过热处理,探索温度诱导的熔体结构转变对SnSb11Cu6、 Al-20Sn、QAl10-4-4三种合金凝固组织及力学性能的影响。课题研究内容与结论如下：1.通过探讨合金(SnSb11Cu6、Al-20Sn、QAl10-4-4)熔体的电阻率-温度关系,实验显示随温度的升高,合金在一定的温度区间内发生了不同特征的异常突变。2.对合金(SnSb11Cu6、Al-20Sn、QAl10-4-4)进行凝固实验,通过凝固后金相组织观察、EDS分析及ⅪD测试对比发现,经熔体过热处理后的合金凝固组织明显细化,合金相的分布更加均匀。分析认为这可能是熔体中的类固型原子团簇经高温过热结构被打破,从而对合金的凝固组织存在一定的影响。3.通过对合金(SnSb11Cu6、Al-20Sn、QAl10-4-4)合金摩擦磨损实验对比发现,经熔体过热处理后的合金摩擦磨损性能得到了明显的改善,合金的摩擦系数明显减小,磨损量变小,硬度增加。分析认为,经熔体过热后的合金凝固组织的细化和均匀的网状分布在很大程度上改善了摩擦磨损过程中较深的犁痕和粘着的发生,并且网状的结构还能储存润滑油,从而改善了合金的耐磨性能。4.分别在一定的温度和外加应力条件下,对SnSb11Cu6、QAl10-4-4合金的蠕变拉伸实验比较发现,经熔体过热处理后的合金试样蠕变第一阶段时间缩短,稳态蠕变阶段的蠕变速率明显减小,稳态阶段时间延长,蠕变时间较长,整个试验过程的蠕变变形量明显小于未经熔体结构转变的合金。充分说明经熔体结构转变的合金的蠕变性能得到明显的改善。
[Abstract]:The solidification behavior and microstructure and properties of the alloy are closely related to the melt structure.At present, alloying, rapid solidification and thermomechanical treatment are the main methods to improve the microstructure of the alloy.Solidification structure and properties are still empirical.In this paper, three typical wear-resistant industrial alloys, SnSb11Cu6AL-20SnOQAl10-44) were studied. The changes of melt structure were studied by the change of melt resistivity, and the melt superheat treatment was carried out.The effect of melt structure transformation induced by temperature on solidification microstructure and mechanical properties of SnSb11Cu6, Al-20SnAQAl10-4-4 alloys was investigated.The research contents and conclusions are as follows: 1.The relationship between resistivity and temperature of Sn-Sb11Cu6AL-20SnOQAl10-4-4) melts was investigated. The experimental results show that with the increase of temperature, the alloy has different characteristics of abnormal mutation in a certain range of temperature.The solidification experiments were carried out on SnSb11Cu6Al-20SnAQAl10-4-4). The microstructure of the alloy after solidification was observed by EDS analysis and compared with the analysis of XI D. It was found that the solidified microstructure of the alloy after melt superheat treatment was obviously refined and the distribution of the alloy phase was more uniform.It is believed that this kind of solid atom cluster in the melt is broken by superheated structure at high temperature, which has a certain influence on the solidification structure of the alloy.By comparing the friction and wear experiments of SnSb11Cu6Al-20SnAQAl10-4-4) alloy, it is found that the friction and wear properties of the alloy after melt superheat treatment have been obviously improved, the friction coefficient of the alloy has been obviously reduced, the wear volume has decreased and the hardness of the alloy has been increased.The analysis shows that the refinement and uniform distribution of solidified microstructure after melt overheating can greatly improve the occurrence of ploughing and adhesion in the process of friction and wear, and the reticular structure can store lubricating oil.Thus, the wear resistance of the alloy was improved.The creep tensile tests of SnSb11Cu6OQAl10-4-4 alloy under certain temperature and applied stress respectively show that the first stage of creep time is shortened and the creep rate of steady state creep phase is obviously reduced after melt superheat treatment.The time of steady state is prolonged and the creep time is longer. The creep deformation of the whole test process is obviously smaller than that of the alloy without melt structure transformation.It is shown that the creep property of the alloy transformed by melt structure has been improved obviously.
【学位授予单位】：安徽工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG135.6

【参考文献】