热处理对选区激光熔化Al-Mn-Mg-Sc-Zr合金力学性能和腐蚀行为的影响
Effect of heat treatment on mechanical property and corrosion behaviour of selective laser melted Al-Mn-Mg-Sc-Zr alloys
邓英 1曹俊昌 2赖毅 2郭一帆 2梁美婵 3潘清林 1徐国富1
作者信息
- 1. 中南大学 材料科学与工程学院,长沙 410083;中南大学 有色金属材料科学与工程湖南省重点实验室,长沙 410083
- 2. 中南大学 材料科学与工程学院,长沙 410083
- 3. 广东伟业铝厂集团有限公司,佛山 528000
- 折叠
摘要
以Al-4.77Mn-1.37Mg-0.67Sc-0.25Zr(质量分数,%)合金粉末为原料,在激光功率330 W和扫描速率700 mm/s下进行选区激光熔化(Selective laser melting,SLM)形成SLM Al-Mn-Mg-Sc-Zr合金,结合慢应变速率拉伸实验、电化学测试、析氢浸泡实验及显微组织表征手段,分析了(350℃,8 h)热处理对SLM Al-Mn-Mg-Sc-Zr合金力学性能和腐蚀行为的影响.结果表明:SLM Al-Mn-Mg-Sc-Zr合金力学性能优异,抗拉强度、屈服强度和伸长率分别为423 MPa、376 MPa和25.1%.热处理后,SLM Al-Mn-Mg-Sc-Zr合金晶内析出大量针棒状纳米Al6Mn相,抗拉强度和屈服强度分别提升至509 MPa和478 MPa.此外,SLM Al-Mn-Mg-Sc-Zr合金具有良好的耐蚀性能,热处理可以促进SLM Al-Mn-Mg-Sc-Zr合金的钝化,在-0.5 V极化电位时出现钝化台阶,降低SLM Al-Mn-Mg-Sc-Zr合金的电流密度,增加SLM Al-Mn-Mg-Sc-Zr合金的阳极极化率,使SLM Al-Mn-Mg-Sc-Zr合金的平均析氢速率从0.242 mL/(cm2·h)降至0.216 mL/(cm2·h),应力腐蚀敏感因子从 3.379%降至0.405%.与此同时,热处理也促进了晶内微米富Si相以及晶界富Mn相和Mg相的析出,增加了SLM Al-Mn-Mg-Sc-Zr合金点蚀形核位置,增大了SLM Al-Mn-Mg-Sc-Zr合金的晶界电化学成分非均匀性,降低了SLM Al-Mn-Mg-Sc-Zr合金的点蚀和晶间腐蚀抗力.
Abstract
The selective laser melted(SLM)alloy was prepared at laser power of 330 W and scanning speed of 700 mm/s using Al-4.77Mn-1.37Mg-0.67Sc-0.25Zr(mass fraction,%)alloy powder as raw material.The effects of heat treatment(350℃,8 h)on mechanical properties and corrosion behavior of SLM Al-Mn-Mg-Sc-Zr alloy were analyzed by slow strain rate tensile test,electrochemical test,hydrogen evolution test and microstructure characterization.The results show that the mechanical properties of SLM Al-Mn-Mg-Sc-Zr alloy are excellent,the tensile strength,yield strength and elongation reach 423 MPa,376 MPa and 25.1%,respectively.After heat treatment,a large number of needle-like or rod-like Al6Mn phases precipitate,and the tensile strength and yield strength further increase to 509 MPa and 478 MPa,respectively.In addition,SLM Al-Mn-Mg-Sc-Zr alloy has good corrosion resistance,heat treatment can promote the passivation of SLM Al-Mn-Mg-Sc-Zr alloy at polarization potential of-0.5 V,decrease the current density of SLM Al-Mn-Mg-Sc-Zr alloy and increase anode polarizability of SLM Al-Mn-Mg-Sc-Zr alloy.Therefore,the average hydrogen evolution rate of SLM Al-Mn-Mg-Sc-Zr alloy decreases from 0.242 mL/(cm2·h)to 0.216 mL/(cm2·h),and the stress corrosion sensitivity factor of SLM Al-Mn-Mg-Sc-Zr alloy decreases from 3.379%to 0.405%.At the same time,the heat treatment can also accelerate the precipitation of micron-scaled Si-rich phase of SLM Al-Mn-Mg-Sc-Zr alloy in grains and Mn and Mg enriched grain boundary phases,which increases the nucleation sites of pitting corrosion nucleation and the non-uniformity of the electrochemistry at the grain boundary,reduces resistance to pitting corrosion and intergranular corrosion.
关键词
选区激光熔化/热处理/应力腐蚀/晶间腐蚀/电化学/显微组织Key words
selective laser melting/heat treatment/stress corrosion/inter-granular corrosion/electrochemistry/microstructure引用本文复制引用
基金项目
湖南省自然科学基金(2023JJ30671)
长沙市自然科学基金(KQ2208264)
湖南省青年骨干教师项目(150220001)
国家重点研发计划(2021YFC1910505)
广东省重点领域研发计划(2020B010186002)
出版年
2024
NETL
NSTL
维普
万方数据