不同铸型下Al-6.5Mg-0.14Ti-0.12Zr合金的微观组织与力学性能
|
摘要
采用熔模铸造、树脂砂铸造和石膏型铸造等方式成形Al-6.5Mg-0.14Ti-0.12Zr合金,由凝固冷却曲线可知合金凝固温度区间为111.4℃,其中熔模铸造凝固冷速最高,树脂砂铸造次之,石膏型铸造最低。Al-6.5Mg-0.14Ti-0.12Zr合金流动性较佳,可实现不同铸型的完整充型,凝固过程未观察到明显的铸件/铸型界面反应。合金铸态组织主要由α-Al相与Al_3Mg_2相组成,Al_3Mg_2相沿晶界均匀分布,与石膏型铸造相比,树脂砂铸造试样中α-Al相平均尺寸由324μm降至132μm;熔模铸造试样抗拉强度、屈服强度、伸长率与硬度(HV)分别为274.7MPa、136MPa、14.9%与60,经400℃×12h固溶后,本体试样抗拉强度、屈服强度、伸长率与硬度(HV)分别增至322.7MPa、144MPa、31.9%与68.3。铸态断口以沿晶断裂为主,可见少量微观韧窝;经固溶处理后断裂方式以韧性断裂为主,韧窝内可见少量的Al_3Mg_2相、Al_3Ti相与Al_3Zr相颗粒。
The solidification cooling curve of Al-6.5 Mg-0.14 Ti-0.12 Zr is distributed according with the Logarithm function,which presents as paste solidification easily due to the temperature interval of 111.4℃.The investment mold obtains the highest cooling rate,which is higher than the resin sand and plaster mold.Absence of casting/mold interface reaction can be observed during the solidification process,and the alloy has excellent filling capability,which can fill completely the different molds.The as-cast microstructure of the alloy is composed ofα-Al phase and Al_3Mg_2 phase,and the Al_3Mg_2 phase is distributed uniformly along the grain boundary.The average size ofα-Al phase can be reduced from 324μm to 132μm in resin casting compared with that of ones in plaster mold casting.The average tensile strength,yield strength,elongation and Vickers hardness of investment casting samples reach up to 274.7 MPa、136 MPa、14.9% and 60 HV,respectively.After the solid solution treatment at 400℃for 12 h,the average tensile strength,yield strength,elongation and Vickers hardness of the investment casting samples are increased to 322.7 MPa、144 MPa、31.9% and 68.3 HV,respectively.The as-cast fracture is presented absolutely crystal fracture,and some micro-dimples can be observed.The rupture mode is changed to dimple fracture after the solution treatment,and small Al_3Mg_2 phase,Al_3Ti phase and Al_3Zr phase particles are generated in the dimple.
The solidification cooling curve of Al-6.5 Mg-0.14 Ti-0.12 Zr is distributed according with the Logarithm function,which presents as paste solidification easily due to the temperature interval of 111.4℃.The investment mold obtains the highest cooling rate,which is higher than the resin sand and plaster mold.Absence of casting/mold interface reaction can be observed during the solidification process,and the alloy has excellent filling capability,which can fill completely the different molds.The as-cast microstructure of the alloy is composed ofα-Al phase and Al_3Mg_2 phase,and the Al_3Mg_2 phase is distributed uniformly along the grain boundary.The average size ofα-Al phase can be reduced from 324μm to 132μm in resin casting compared with that of ones in plaster mold casting.The average tensile strength,yield strength,elongation and Vickers hardness of investment casting samples reach up to 274.7 MPa、136 MPa、14.9% and 60 HV,respectively.After the solid solution treatment at 400℃for 12 h,the average tensile strength,yield strength,elongation and Vickers hardness of the investment casting samples are increased to 322.7 MPa、144 MPa、31.9% and 68.3 HV,respectively.The as-cast fracture is presented absolutely crystal fracture,and some micro-dimples can be observed.The rupture mode is changed to dimple fracture after the solution treatment,and small Al_3Mg_2 phase,Al_3Ti phase and Al_3Zr phase particles are generated in the dimple.
引文
[1]郭海洋,陈体军,段天全,等.Mg含量对金属型铸造Al-Mg合金的微观组织和枝晶形貌的影响[J].铸造,2013,62(4):319-323,329.
[2]李晓峰,党惊知,程军,等.过滤对铸造Al-Mg合金性能和组织的影响[J].热加工工艺,2010,39(9):61-62.
[3]吴兵,刘颖峰.AC7A铝镁合金端盖的铸造工艺[J].特种铸造及有色合金,2009,29(9):816-819.
[4]胥健秋,殷云霞,胡爽,等.一种含Sc元素Al-Mg合金熔铸工艺研究[J].有色设备,2018(5):43-48.
[5]赵海,吉猛,王光东,等.Mg含量对Al-xMg合金板材显微组织的影响[J].轻合金加工技术,2018,46(5):18-23.
[6]安勇良,尹冬松,谭志强.Gd对Al-Mg合金微观组织和力学性能的影响[J].黑龙江科技大学学报,2017,27(6):670-673.
[7]葛丽丽,程仁策,吕正风,等.Mn含量对Al-Mg合金板材组织与性能的影响[J].金属热处理,2017,42(5):14-17.
[8]陈超,刘勇,张振富,等.Fe、Mn、Ce对压铸Al-Mg和Al-Mg-Si合金组织和性能的影响[J].铸造,2017,66(4):337-340.
[9]郑红梅,胡学飞,崔接武,等.添加Sc元素后Al-Mg合金的性能和结构变化[J].材料热处理学报,2016,37(11):45-49.
[10]贺志荣,刘继拓,解亚丹,等.Al和Si对热浸Zn-Al-Mg合金镀层组织和耐腐蚀性的影响[J].中国有色金属学报,2015,25(5):1 250-1 255.
[11]许秀芝,向茜,谭颖,等.连续挤压Al-Mg合金管的稳定化热处理研究[J].轻合金加工技术,2015,43(4):55-61.
[2]李晓峰,党惊知,程军,等.过滤对铸造Al-Mg合金性能和组织的影响[J].热加工工艺,2010,39(9):61-62.
[3]吴兵,刘颖峰.AC7A铝镁合金端盖的铸造工艺[J].特种铸造及有色合金,2009,29(9):816-819.
[4]胥健秋,殷云霞,胡爽,等.一种含Sc元素Al-Mg合金熔铸工艺研究[J].有色设备,2018(5):43-48.
[5]赵海,吉猛,王光东,等.Mg含量对Al-xMg合金板材显微组织的影响[J].轻合金加工技术,2018,46(5):18-23.
[6]安勇良,尹冬松,谭志强.Gd对Al-Mg合金微观组织和力学性能的影响[J].黑龙江科技大学学报,2017,27(6):670-673.
[7]葛丽丽,程仁策,吕正风,等.Mn含量对Al-Mg合金板材组织与性能的影响[J].金属热处理,2017,42(5):14-17.
[8]陈超,刘勇,张振富,等.Fe、Mn、Ce对压铸Al-Mg和Al-Mg-Si合金组织和性能的影响[J].铸造,2017,66(4):337-340.
[9]郑红梅,胡学飞,崔接武,等.添加Sc元素后Al-Mg合金的性能和结构变化[J].材料热处理学报,2016,37(11):45-49.
[10]贺志荣,刘继拓,解亚丹,等.Al和Si对热浸Zn-Al-Mg合金镀层组织和耐腐蚀性的影响[J].中国有色金属学报,2015,25(5):1 250-1 255.
[11]许秀芝,向茜,谭颖,等.连续挤压Al-Mg合金管的稳定化热处理研究[J].轻合金加工技术,2015,43(4):55-61.