(山東理工大學(xué) 機(jī)械工程學(xué)院，淄博 255049)
摘 要: 平均晶粒尺寸為150 μm的工業(yè)黃銅H68初始樣品經(jīng)晶界工程(GBE)處理，其特殊晶界比達(dá)到76%、平均晶粒尺寸為30 μm。拉伸實(shí)驗(yàn)和銨鹽環(huán)境中的腐蝕實(shí)驗(yàn)結(jié)果表明：經(jīng)GBE處理的樣品，不僅其抗拉強(qiáng)度由初始樣品的234 MPa提高到297 MPa，且其晶界腐蝕抗力也得到顯著改善。相比于同樣晶粒尺寸的傳統(tǒng)再結(jié)晶狀態(tài)樣品，經(jīng)GBE處理的樣品，雖其抗拉強(qiáng)度降低，但其伸長率卻提高17%；前者在銨鹽環(huán)境中沿晶腐蝕嚴(yán)重，而后者基本不發(fā)生沿晶腐蝕。GBE處理的樣品中存在的大量特殊晶界(主要是 晶界)及其對(duì)一般大角度晶界網(wǎng)絡(luò)連通性的阻斷是該樣品比初始樣品以及傳統(tǒng)再結(jié)晶樣品具有優(yōu)異晶界腐蝕抗能力的主要原因；特殊晶界雖然具有明顯的界面強(qiáng)化作用，但其強(qiáng)化效果顯然不如一般大角度晶界，其原因可能與特殊晶界具有較高結(jié)構(gòu)有序度有關(guān)。
關(guān)鍵字: H68黃銅；晶界；GBE處理；腐蝕；力學(xué)性能
mechanical properties of brass H68
（School of Mechanical Engineering, Shandong University of Technology, Zibo 255049, China）
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 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.
Key words: brass H68; grain boundary; GBE processing; corrosion; mechanical property
