多元合金化高性能铝硅合金活塞的研究

发布时间：2018-06-11 20:56

本文选题：铝硅合金 + 合金化　；参考：《合肥工业大学》2017年硕士论文

【摘要】：发动机性能的不断提高对活塞的耐磨、耐热等性能也提出了更高的要求,因此需要开发出性能更高的活塞用铝硅合金。本文对共晶铝硅合金和过共晶铝硅合金(w(Si)=20%),分别进行多元合金化成分设计,通过变质处理和热处理,获得了高性能铝硅合金活塞材料。所得的主要结果和结论如下:(1)研究了稀土La和Sr对共晶铝硅合金的变质效果和作用。结果表明:当加入1.2%La时,共晶硅从针片状变为短杆状,平均尺寸从未变质时的84μm下降为38μm。当加入0.06%~0.08%Sr时,共晶硅从针片状变为纤维状,平均尺寸大幅下降到2μm左右,数量显著增加且分布均匀。对于共晶铝硅合金,Sr具有比稀土La更加优异的变质效果。(2)研究了多元合金化对共晶铝硅合金活塞力学性能的影响。采取Cu、Ni、Mg、Ti、Zn等元素进行多元合金化,其中Cu的加入量为3.0%~3.5%,Ni的加入量为1.0%~3.0%。结果表明:在0.06%的Sr变质、510℃固溶6h和185℃时效6h的条件下,随着Cu含量的增加,共晶铝硅合金的室温强度和高温强度均大幅度提高,随着Ni含量的增加,合金室温性能提高,特别是显著提高合金的高温强度。当Cu含量为3.5%,Ni含量为2.0%时,共晶铝硅合金活塞室温抗拉强度达到303.06MPa,300℃下高温抗拉强度达到137.74MPa,洛氏硬度(HRB)为81.7。(3)研究了热处理对共晶铝硅合金活塞组织和性能的影响。结果表明:固溶热处理能够显著改善共晶硅的形态和分布。经过510℃固溶6h后,共晶硅尺寸变小,棱角趋于圆整。在经过185℃时效6h后,合金强化相数量增多,分布均匀,棱角圆整,合金硬度升高。(4)研究了P变质和P+La复合变质对过共晶铝硅合金组织的影响。结果表明:当加入0.06%的P时,初晶硅的平均尺寸从未变质时的122μm下降为29μm,形状因子从未变质时的0.21上升到0.82,且数量增多,分布均匀。采用0.06%P+0.9%La复合变质,能够对初晶硅和共晶硅组织同时取得最佳的复合变质效果。(5)研究了多元合金化对过共晶铝硅合金活塞力学性能的影响。采取Cu、Ni、Mg、Ti、Zn等元素进行多元合金化,其中Cu的加入量为1.0%~3.0%,Ni的加入量为1.0%~1.5%。结果表明:在0.06%P+0.9%La的复合变质、510℃固溶6h和185℃时效6h的条件下,随着Cu含量的增加,共晶铝硅合金的室温强度和高温强度均大幅度提高,随着Ni含量的增加,合金室温性能提高,特别是显著提高合金的高温强度。当Cu含量为3.0%,Ni含量为1.5%时,过共晶铝硅合金活塞室温抗拉强度为242.62MPa,300℃高温抗拉强度为127.95MPa。
[Abstract]:The continuous improvement of engine performance has made higher requirements for the wear-resisting and heat-resistant properties of the piston. Therefore, it is necessary to develop a high performance piston with aluminum silicon alloy. In this paper, the composition of eutectic Al Si alloy and hypereutectic Al Si alloy (w (Si) =20%) was designed, and the high properties were obtained by modification and heat treatment. The main results and conclusions obtained are as follows: (1) the modification effect and effect of rare earth La and Sr on eutectic Al Si alloy are studied. The results show that when 1.2%La is added, the eutectic silicon changes from the needle sheet to the short rod, and the average size of the eutectic silicon is reduced to 38 Mu under the 84 m when the average size never metamorphosed. When 0.06%~0.08%Sr is added, the eutectic silicon is from the needle slice. The shape changed into fiber, the average size dropped to about 2 m, the number increased significantly and the distribution was uniform. For the eutectic Al Si alloy, Sr had more excellent modification effect than the rare earth La. (2) the effect of multiple alloying on the mechanical properties of eutectic Al Si alloy piston was studied. The elements of Cu, Ni, Mg, Ti, Zn and other elements were alloyed in multiple alloying, among which Cu The addition of Ni was 3.0%~3.5%, and the addition of 1.0%~3.0%. showed that the room temperature strength and high temperature strength of the eutectic Al Si alloy increased greatly with the increase of Cu content at 0.06% Sr, 510 C solution 6h and 185 C aging 6h. With the increase of Ni content, the properties of the alloy at room temperature were improved, especially the alloy improved remarkably. When the content of Cu is 3.5% and the content of Ni is 2%, the tensile strength of the eutectic Al Si alloy piston reaches 303.06MPa at room temperature, the tensile strength is 137.74MPa at 300 C, and the Rockwell hardness (HRB) is 81.7. (3). The effect of heat treatment on the microstructure and energy of the eutectic Al Si alloy piston is studied. The results show that the solution heat treatment can significantly improve the total heat treatment. The morphology and distribution of crystalline silicon. After solid solution of 6h at 510 degrees C, the size of eutectic silicon is smaller and the angle tends to round. After aging at 185 C, the amount of the alloy strengthening phase increases, the distribution is uniform, the edges and corners are round and the hardness of the alloy increases. (4) the effect of P modification and P+La composite modification on the microstructure of hypereutectic Al Si alloy is studied. The results show that when 0.06% of P is added to the alloy The average size of the primary silicon decreased to 29 mu m at the time of never metamorphic 122, and the shape factor increased to 0.82 when the shape factor never metamorphosed, and the number increased, and the distribution was uniform. The best composite metamorphism could be obtained by 0.06%P+0.9%La composite modification. (5) the polyalloying of Hypereutectic Al Si was studied. The influence of the mechanical properties of the alloy piston was made by multiple alloying of Cu, Ni, Mg, Ti, Zn and so on. The addition of Cu was 1.0%~3.0%, and the amount of Ni added 1.0%~1.5%. showed that the room temperature strength and height of eutectic Al Si alloy increased with the increase of the content of 0.06%P+0.9%La in the compound metamorphism, the 510 C solid solution 6h and the 185 C aging 6h. The temperature strength of the alloy increases with the increase of Ni content, especially at room temperature. When the content of Cu is 3% and the content of Ni is 1.5%, the tensile strength of the hypereutectic Al Si alloy piston is 242.62MPa at room temperature, and the tensile strength at 300 C is 127.95MPa..
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U464.133.1;TG146.21

【相似文献】