Ar/CCl_4联合净化对2219铝合金铸锭组织与力学性能的影响

Effect of Ar/CCl_4 combined purification on microstructure and mechanical properties of 2219 aluminum alloy ingot

借助氢含量检测、金相组织观察、力学性能测试和拉伸断口形貌观察等检测和分析方法,研究Ar/CCl_4联合净化对2219铝合金铸锭的组织与力学性能的影响,并与用固态RFI型精炼剂(简称RFI精炼剂)精炼的合金进行对比,同时,揭示精炼介质对夹杂物和氢的作用机制。结果表明:相对于用Ar/RFI联合精炼,采用Ar/CCl_4联合精炼2219铝合金熔体具有更高的除氢效率,并可有效抑制铸锭中缩松、气孔和夹杂的产生,Ar/RFI联合精炼和Ar/CCl_4联合精炼的除氢率分别为8.57%和17.67%;连续2次采用相同介质精炼时,Ar/CCl_4精炼的二次除氢率(15.4%)比Ar/RFI精炼的二次除氢率(8.57%)高;采用1次Ar/RFI联合精炼+2次Ar/CCl_4联合精炼时铸锭的抗拉强度和伸长率分别达到205.69 MPa和14.5%。此外,相对于1次Ar/RFI联合精炼+1次Ar/CCl_4联合精炼,合金经一次Ar/RFI联合精炼+2次Ar/CCl_4联合精炼后的抗拉强度提高21.63 MPa,伸长率提高4.04%,合金的断裂行为由脆性断裂向韧性断裂转变。

The effects of Ar/CCl4 combined purification on the microstructure and mechanical properties of 2219 aluminum alloy ingot were investigated by metallographic observation, SEM, mechanical properties and hydrogen content testing. The results were compared with that of the alloy refined with solid solvent （RFI）, and the mechanism of refining medium on inclusions and hydrogen in the melt was also revealed. The results show that, compared with the Ar/RFI combined refining, the Ar/CCl4 combined refining has a higher removal efficiency of hydrogen for 2219 aluminum alloy melt. The hydrogen removal rates are 8.57% and 17.67% for Ar/RFI combined refining and Ar/CCl4 combined refining, respectively. After refining the melt with the same medium for two consecutive times, the hydrogen removal rate of the Ar/CCl4 combined refining （15.4%） for the second time of refine is higher than that of the Ar/RFI combined refining （8.57%）. The tensile strength and elongation rate of the ingot casted with the melt treated with Ar/RFI combined refining, and followed by two times of Ar/CCl4 combined refining are 205.69 MPa and 14.5%, respectively. In addition, compared with Ar/RFI combined refining followed by Ar/CCI4 combined refining, a Ar/RFI combined refining followed by two times of Ar/CCl4combined refining results in an increasing of 21.63 MPa and 4.04% for the tensile strength and elongation of the ingot, and the fracture behavior of the alloys transforms from brittle to ductile manner.