Abstract

A new concept to evaluate the localized corrosion resistance of stacked Ti alloys such as additive-manufactured (AM) Ti–6Al–4V alloy is proposed. Crevice corrosion of subtractive-manufactured (SM) Ti–6Al–4V occurred on the surface beneath the crevice former, whereas localized corrosion of the AM alloy occurred in any vulnerable site irrespective of the crevice assembly. The electrochemical critical localized corrosion temperature (E-CLCT) was measured to evaluate the resistance of AM Ti–6Al–4V alloys to localized corrosion. The results showed that the localized corrosion of AM Ti–6Al–4V was attributable to the anisotropy and microstructure that resulted from rapid cooling, which were completely different from the anisotropy and microstructure of SM Ti–6Al–4V. The optimum applied potential of AM Ti–6Al–4V in 25 wt% NaCl aqueous solution was deduced. The E-CLCT provides a useful criterion for determining the resistance of AM Ti alloys to localized corrosion and for comparing their resistances.

Graphic abstract

The shape of localized corrosion on additive-manufactured Ti–6Al–4V alloy.

中文翻译：

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使用电化学临界局部腐蚀温度评估增材制造的Ti-6Al-4V的耐腐蚀性

摘要

提出了一种新的概念来评估叠层Ti合金（如增材制造（AM）Ti-6Al-4V合金）的局部耐蚀性。减法制造（SM）Ti–6Al–4V的缝隙腐蚀发生在缝隙形成器下方的表面上，而AM合金的局部腐蚀发生在任何易受腐蚀的部位，而与缝隙组件无关。测量了电化学临界局部腐蚀温度（E-CLCT），以评估AM Ti-6Al-4V合金对局部腐蚀的抵抗力。结果表明，AM Ti-6Al-4V的局部腐蚀归因于快速冷却导致的各向异性和微观结构，这与SM Ti-6Al-4V的各向异性和微观结构完全不同。推导了AM Ti-6Al-4V在25 wt％NaCl水溶液中的最佳施加电势。

图形摘要

添加剂制造的Ti-6Al-4V合金的局部腐蚀形状。