铸锻复合对ADC12铝合金显微组织和性能的影响  

Microstructure and Properties of ADC12 Aluminum Alloy Improved by Casting-forging Combined Forming

作　　者：熊禹[1] 吉泽升[1] 徐丽娟 

机构地区：[1]哈尔滨理工大学材料科学与工程学院 [2]哈尔滨吉星机械工程有限公司

出　　处：《特种铸造及有色合金》2017年第2期214-217,共4页Special Casting & Nonferrous Alloys

基　　金：黑龙江省国际合作项目(2015WB15C104);哈尔滨市科技攻关项目(2015AB4AG004)

摘　　要：通过铸锻复合工艺加工ADC12铝合金,该工艺包括间接挤压铸造和锻造,分别对重力铸造态、挤压铸造态和铸锻复合态的ADC12铝合金的力学性能和显微组织进行了研究。结果表明,挤压铸造的ADC12铝合金具有更细的Al-Si共晶组织,针状共晶组织减少,其平均晶粒尺寸为37.25μm,较重力铸造态降低了36.51%,其抗拉强度和伸长率分别为240MPa和1%,较重力铸造的分别提高了34.08%和14.9%;铸锻复合后,组织进一步细化,Al-Si共晶组织被压碎,其平均晶粒尺寸为26.54μm,较重力铸造降低了28.75%,其抗拉强度和伸长率分别达到287.75 MPa和4.4%,较挤压铸造态分别提高了19.8%和340%。从拉伸断口形貌上可发现,铸态断口为典型的脆性断口,挤压铸造和铸锻复合后,都属准解理断裂,但是铸锻复合后,韧窝更浅而小,解理面和撕裂棱变得细小,断裂单元变小,韧性断裂趋势增加。经分析,晶粒细化及Al-Si共晶组织分布状态的改变是ADC12合金抗拉强度和伸长率提高的主要因素。ADC12aluminum alloy was prepared by casting-forging compound forming,which included indirect squeeze casting and forging,and tensile properties and microstructure of the ADC12 alloy in metal mold casting,indirect squeeze casting and forging after indirect squeeze casting were investigated.The results reveal that after indirect squeeze casting,the dendrites in the alloy become fine spherical structure and number of Al-Si eutectic structure is decreased with average grain size of 37.25μm,decreased by 36.51%,and the tensile strength and elongation reach 240 MPa and 1%,improved by about 34.08%and 14.9%,respectively,compared with those of the metal alloy.Compared with squeeze casting,after casting-forging,theα-Al grains in the ADC alloy are refined obviously,and Al-Si eutectic structures can be crushed and uniformly dispersed in the microstructure with average grain size of 37.25μm,decreased by 28.75%.Meanwhile,the tensile strength and elongation reach 287.75 MPa and 4.4%,improved by about 19.8% and 340%,respectively,compared with those of the metal alloy.The fracture modes of the billet prepared by the metal mold casting are characterized by intergranular fractures,whereas,both that of the indirect squeeze casting and forging after indirect squeeze casting are characterized by quasicleavage fractures.However,after forging,the dimples become more shallow and small,and the number of dimple is increased,so the plastic fracture tendency is increased.The fine grain strengthening and the distribution of Al-Si eutectic structures are responsible for improving the strength and elongation of ADC12 aluminum alloy.

关 键 词：间接挤压铸造 锻造 铸锻复合 ADC12合金 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG249[金属学及工艺—金属材料]