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在5%NaCl水溶液中通过浸泡和电化学测试研究铸态与挤压态Mg-5Y-7Gd-1Nd-0.5Zr镁合金的腐蚀性能。铸态和挤压态Mg-5Y-7Gd-1Nd-0.5Zr镁合金的平均晶粒尺寸分别为100μm和15μm。在腐蚀初期,铸态合金的腐蚀形貌为点蚀和少量丝状腐蚀,挤压态合金的腐蚀形貌为点蚀。挤压态合金的腐蚀速率大于铸态合金的腐蚀速率。包含稀土的第二相在合金中作为阴极,改善了合金的腐蚀性能。铸态与挤压态合金的腐蚀电位分别为-1.658V和-1.591V。探讨了铸态与挤压态合金腐蚀性能不同的原因。
Corrosion behavior of as-cast and as-extruded Mg-5Y-7Gd-1Nd-0.5Zr magnesium alloys was investigated by immersion and electrochemical tests in 5% NaCl aqueous solution. The average grain sizes of as-cast and as-extruded Mg-5Y-7Gd-1Nd-0.5Zr magnesium alloys were 100μm and 15μm, respectively. In the initial stage of corrosion, the corrosion morphology of as-cast alloy is pitting corrosion and a few filamentous corrosion. The corrosion morphology of extruded alloy is pitting corrosion. The corrosion rate of the extruded alloy is greater than the corrosion rate of the as-cast alloy. The second phase, which contains rare earth, acts as a cathode in the alloy, improving the corrosion properties of the alloy. The corrosion potentials of as-cast and extruded alloys are -1.658V and -1.591V, respectively. The reasons for the different corrosion behaviors of as-cast and extruded alloys were discussed.