搅拌摩擦加工对AZ31镁合金腐蚀行为的影响

Effect of friction stir processing on corrosion behavior of AZ31 magnesium alloy

为了探究搅拌摩擦加工对AZ31镁合金腐蚀性能的影响,采用体视镜、光学显微镜、接触角测量仪、电化学工作站等设备研究了AZ31母材与不同工艺参数下FSP-AZ31在3.5 wt.%NaCl溶液中的腐蚀行为。结果表明:在转速800~1200 r/min、加工速度80~120 mm/min范围内,FSP-AZ31与母材腐蚀机制均为点蚀。与母材相比,FSP-AZ31点蚀程度较轻,自腐蚀电流密度减小,阻抗增大,FSP均能够提高AZ31镁合金的耐腐蚀性能。当加工速度为100 mm/min时,随着旋转速度增大,FSP-AZ31自腐蚀电流密度不断减小,耐腐蚀性能不断提升。试样在旋转速度为1200 r/min时自腐蚀电流密度达到最小值9.2×10^(-5)A·cm^(-2)。当旋转速度为1000 r/min时,随着加工速度减小,FSP-AZ31自腐蚀电流密度不断减小,耐腐蚀性能不断提升。在加工速度为80 mm/min时试样的自腐蚀电流密度达到最小,其值为7.6×10^(-5)A·cm^(-2)。相比AZ31镁合金,1000 r/min和80 mm/min条件下FSP-AZ31的接触角由29.703°上升至58.448°。

In order to investigate the effect of friction stir processing on the corrosion performance of AZ31 magnesium alloy,the corrosion behavior of AZ31 base material and FSP-AZ31 under different process parameters in 3.5 wt.%sodium chloride solution was studied using stereoscopy,optical microscopy,contact angle measurement,electrochemical workstation and other equipments.The results show that the corrosion mechanism of FSP-AZ31 and the base metal is pitting corrosion in the range of rotating speed 800-1200 r/min and processing speed 80-120 mm/min.Compared with the base metal,FSP-AZ31 has a lighter degree of pitting corrosion,the self-corrosion current density is reduced,the impedance is increased,and FSP can improve the corrosion resistance of AZ31 magnesium alloy.When the processing speed is 100 mm/min,as the rotation speed increases,the self-corrosion current density of FSP-AZ31 is continuously decreased,and the performance of corrosion resistance is continuously improved.When the rotation speed is 1200 r/min,the self-corrosion current density of the sample reaches the minimum value of 9.2×10^(-5)A·cm^(-2).When the rotation speed is 1000 r/min,as the processing speed decreases,the self-corrosion current density of FSP-AZ31 is continuously decreased,and the performance of corrosion resistance is continuously improved.When the processing speed is 80 mm/min,the corrosion current density of the sample reaches the minimum,with a value of 7.6×10^(-5)A·cm^(-2).Compared to AZ31 magnesium alloy,the contact angle of FSP-AZ31 is increased from 29.703°to 58.448°under 1000 r/min and 80 mm/min.