【摘要】 平均晶粒尺寸为150μm的工业黄铜H68初始样品经晶界工程(GBE)处理,其特殊晶界比达到76%、平均晶粒尺寸为30μm。拉伸实验和铵盐环境中的腐蚀实验结果表明:经GBE处理的样品,不仅其抗拉强度由初始样品的234 MPa提高到297 MPa,且其晶界腐蚀抗力也得到显著改善。相比于同样晶粒尺寸的传统再结晶状态样品,经GBE处理的样品,虽其抗拉强度降低,但其伸长率却提高17%;前者在铵盐环境中沿晶腐蚀严重,而后者基本不发生沿晶腐蚀。GBE处理的样品中存在的大量特殊晶界(主要是Σ3晶界)及其对一般大角度晶界网络连通性的阻断是该样品比初始样品以及传统再结晶样品具有优异晶界腐蚀抗能力的主要原因;特殊晶界虽然具有明显的界面强化作用,但其强化效果显然不如一般大角度晶界,其原因可能与特殊晶界具有较高结构有序度有关。更多还原

【Abstract】 A sample of brass H68 with average grain size of 150 μm was subjected to a GBE processing,a grain boundary character distribution(GBCD) containing special boundary percentage of 76% and an average grain size of 30 μm was obtained.The results of tension and corrosion test indicate that GBE processing can not only obviously improve the ultimate strength from its initial value 234 MPa to 297 MPa,but also drastically increase the intergranular corrosion resistance.Compared with the conventionally recrystallized sample with the same average grain size,the ultimate strength of GBE processed sample drops to some extent,but its ductility increases by 17%.The former exhibits a severe intergranular corrosion cracking,while the later appears to be nearly immune to intergranular corrosion attacking.A great deal of special grain boundaries(especially the Σ 3 boundaries) formed in the GBE processed sample and their effective interruption to the connectivity of general high angle boundary networks accounts for primarily its excellent anti-corrosion behavior were discussed further.Although the special grain boundaries demonstrate their effective hardening,it is obviously weaker than that of general high angle boundaries.This might be attributed to the higher degree of ordering in the special boundaries.更多还原