摘要
运用正交设计方法研究了P＋RE＋Sr三元复合变质对Al-28%Si活塞合金铸态组织及T6热处理后性能的影响。结果表明：复合变质剂的加入量对初晶硅细化作用的影响较大,初晶硅平均尺寸在20.91~42.5μm间变化,并通过拟合回归曲线及建立初晶硅受力模型说明初晶硅尺寸和形态对其力学性能有较大影响;通过极差分析得到复合变质剂最佳加入量为0.3%P＋1.0%RE＋0.06%Sr;验证试验也表明,初晶硅平均尺寸L可一次细化至17.75μm,共晶硅呈细小颗粒状,300℃瞬时高温抗拉强度较未变质时提高50%;高温拉伸断口SEM分析表明,未变质试样断口存在粗大的初晶硅,呈脆性断裂,优化复合变质后,初晶硅细小,呈具有大量韧窝的混合状断口。
The P＋RE＋Sr compound modified Al-28%Si piston alloy was investigated by orthogonal test.The results show that the addition amount of the compound modifier has a significant effect on the primary silicon refinement,the average dimension of primary silicon varies from 20.91 μm to 42.5 μm,and the dimension and shape of primary silicon also have big effect on the mechanical properties of the alloy,which were illuminated by the fitted curve and force model.The optimal addition amount of the modifier is 0.3%P＋1.0%RE＋0.06%Sr by range analysis.The experimental results also show that the average dimension of primary silicon can be refined to 17.75 μm,and the instant high-temperature tensile strength at 300 ℃ is 50% larger than that of the alloy unmodified;the fracture SEM showing that the coarse primary silicon is observed in the alloy unmodified,and the fracture belongs to the brittle fracture,while that of the alloy after modification the primary silicon is fine,and the fracture is blended with many dimples.
出处
《铸造》
CAS
CSCD
北大核心
2010年第9期920-923,928,共5页
Foundry
关键词
复合变质
初晶硅
高温抗拉强度
断口
compound modification
primary silicon
high temperature tensile strength
fracture
