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本文研究了7050铝合金的应力腐蚀开裂。用离子探针证实氢在裂尖区富集,通过俄歇能谱分析研究了 Zn,Mg 元素在晶界的偏析。应力腐蚀开裂包括三个过程:(1)在欠时效和峰时效的合金中,氢加速进入晶界;(2)氢和 Zn(或Mg)在位错芯部发生电荷转移产生 H-;(3)由于H-在晶界的尺寸失配导致晶界开裂。测定了应力腐蚀开裂激活能,表明氢在晶界中通过空位扩散是控制应力腐蚀开裂的主要过程。
This paper studies the stress corrosion cracking of 7050 aluminum alloy. Hydrogen was confirmed to be enriched in the crack tip region by ion probe. The segregation of Zn and Mg at grain boundaries was studied by Auger energy spectrum analysis. Stress corrosion cracking consists of three processes: (1) hydrogen accelerates into grain boundaries in an under-aged and peak-aged alloy; (2) hydrogen and Zn (or Mg) undergo charge transfer in the core to produce H-; ( 3) Grain boundaries crack due to H-size mismatch in grain boundaries. The activation energy of stress corrosion cracking was measured. It is shown that the diffusion of hydrogen through the vacancy in the grain boundary is the main process to control the stress corrosion cracking.