铸造Al-Si-Cu-Mg合金多级时效工艺参数优化  

Parameter optimization of multi-step aging process for casting Al-Si-Cu-Mg alloy

作　　者：宋倩 刘德华 文超 石磊 SONG Qian;LIU Dehua;WEN Chao;SHI Lei(CRRC Qishuyan Co.,Ltd.,Changzhou,Jiangsu 213011,China)

机构地区：[1]中车戚墅堰机车车辆工艺研究所有限公司,江苏常州213011

出　　处：《轨道交通材料》2023年第3期46-50,共5页MATERIALS FOR RAIL TRANSPORTATION SYSTEM

摘　　要：将ZL111合金分别进行单级时效及不同工艺参数的多级时效热处理工艺,利用万能试验机、布氏硬度测试(HB)、光学显微镜(OM)及扫描电子显微镜(SEM)等方法系统地研究不同时效热处理工艺后的力学性能、硬度、微观组织及断口情况的变化规律。采用正交试验法梳理了多级时效工艺参数对ZL111合金力学性能的影响程度,并筛选出对抗拉强度、屈服强度、延伸率及硬度影响最大的参数。结果表明:与单级时效工艺相比,多级时效工艺可显著改善ZL111合金的伸长率,最高可达单级时效的2.86倍,对抗拉强度、屈服强度及硬度改善能力相对较弱。固溶时效处理后α-Al基体与共晶体分布均匀,共晶硅为点状,且存在一定量的富铁相;拉伸断口无明显颈缩现象,裂纹源生成于断口表面,第二相质点多为球状及棒状,空洞在第二相处形成,在正应力作用下形成等轴韧窝。与单级时效相比,多级时效后析出相尺寸较小,数量较多,分布较均匀;此外,韧窝较深,综合尺寸较大。Single-step aging treatment and multi-step aging treatment with different technical parameters are implemented for ZL111 alloy,the change law of its mechanical properties,hardness,microstructures and fractures after different aging treatment processes are systematically studied by the aid of the universal tester,HB hardness tester,optical microscope and SEM.The influence of multi-step aging treatment parameters on the mechanical properties of ZL11 alloy is analyzed with orthogonal test,sorting out the parameters which affect most the tensile strength,yield strength,elongation and hardness.Compared with single step aging process,test results show that multi-step aging treatment can significantly improve the elongation of ZL111 alloy,up to 2.86 times as high as that with single step aging treatment,but has less effect on the improvement of tensile strength,yield strength and hardness.After solid solution aging treatment,α-Al base material and the eutectic distributes evenly with punctiform eutectic silicon and some iron-rich phase;the tensile fracture shows no necking,and the cracking originates in the fracture surface;the particles in the second phase are mostly globular and rodlike,and the cavity generates in the second phase and forms paraxial dimple under normal stress.Compared with the single step aging process,multi-step aging treatment produces large amount of well-distributed and small precipitated phase;in addition,it also generates deep dimples and large overall dimensions.

关 键 词：铸造 ZL111合金 正交试验 多级时效 

分 类 号：U270.64[机械工程—车辆工程] TG136.1[交通运输工程—载运工具运用工程]