性能的影響
(中南大學(xué) 粉末冶金研究院，長沙 410083)
摘 要: 采用鑄錠冶金法制備Al-Zn-Mg-Cu-Zr、Al-Zn-Mg-Cu-Cr-Pr和Al-Zn-Mg-Cu-Zr-Cr-Pr 3種合金，通過金相顯微、掃描電鏡和透射電鏡觀察以及拉伸性能、極化曲線、應(yīng)力腐蝕和剝落性能的測試，研究復(fù)合添加Zr、Cr和Pr對Al-Zn-Mg-Cu合金組織和性能的影響。結(jié)果表明：復(fù)合添加Zr、Cr和Pr可有效抑制Al-Zn-Mg-Cu合金回復(fù)過程中亞晶的合并和長大，顯著抑制再結(jié)晶，提高合金抗應(yīng)力腐蝕和抗剝落腐蝕的性能；與單獨添加Zr的合金相比，復(fù)合添加Zr、Cr和Pr的合金斷裂韌性KⅠC從23.3 MPa∙m1/2提高到29.3 MPa∙m1/2，合金應(yīng)力腐蝕開裂界限應(yīng)力強度因子KⅠSCC由10.9 MPa·m1/2提高到24.5 MPa·m1/2，合金的抗拉強度、屈服強度及伸長率都略有提高。
關(guān)鍵字: Al-Zn-Mg-Cu合金；微觀組織；Pr；力學(xué)性能；腐蝕性能
and properties of Al-Zn-Mg-Cu alloys
（Institute of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:Three kinds of alloys Al-Zr-Mg-Cu-Zr, Al-Zn-Mg-Cu-Cr-Pr and Al-Zn-Mg-Cu-Zr-Cr-Pr were prepared by cast metallurgy. The effects of Zr, Cr and Pr additions on the microstructure and properties of Al-Zn-Mg-Cu alloys were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy, tensile test, polarization curve measurement, stress corrosion and exfoliation corrosion test. The results show that the combined additions of Zr, Cr and Pr to the Al-Zn-Mg-Cu alloys effectively retard the mergence and growth of the sub-grain during the recovery process, significantly inhibits the recrystallization of Al matrix, thus enhances the resistance to stress corrosion and exfoliation corrosion. Compared with the Al-Zn-Mg-Cu alloy added with Zr, the complex additions of Zr, Cr and Pr into the Al-Zn-Mg-Cu alloy remarkably increase the fracture toughness (KⅠC) from 23.3 MPa∙m1/2 to 29.3 MPa∙m1/2, and enhance the resistance to stress corrosion cracking (KⅠSCC) from 10.9 MPa·m1/2 to 24.5 MPa·m1/2, yield strength and elongation of the alloys all increase a little.
Key words: Al-Zn-Mg-Cu alloys; microstructure; praseodymium; mechanical properties; corrosion properties
