(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；
2.長沙南方鉭鈮有限責(zé)任公司，長沙 410133；
3. 中南大學(xué) 輕質(zhì)高強結(jié)構(gòu)材料重點實驗室，長沙 410083；
4. 中南大學(xué) 粉末冶金國家重點實驗室，長沙 410083；
5. 有色金屬材料科學(xué)與工程教育部重點實驗室，長沙 410083)
摘 要: 利用力學(xué)、電學(xué)性能測試，EBSD分析和透射電鏡觀察，研究冷鍛態(tài)(變形量為56%)、375 ℃退火處理和375 ℃退火+600 ℃真空蠕變時效處理態(tài)Cu-0.05%Al2O3彌散強化銅合金的力學(xué)性能和組織結(jié)構(gòu)的演變規(guī)律。結(jié)果表明：原始狀態(tài)即冷鍛變形態(tài)合金的抗拉強度為354 MPa、屈服強度為345 MPa、伸長率為9.6%、電導(dǎo)率為94.5%IACS。在對冷鍛態(tài)試樣進行375 ℃退火處理后，合金的屈服強度下降1.7%，但電導(dǎo)率提升0.5%；在375 ℃退火處理的基礎(chǔ)上，對合金進行600 ℃、6 h真空蠕變時效處理，相比于冷鍛變形態(tài)，蠕變時效后的樣品屈服強度下降9.6%，但電導(dǎo)率提高1.6%。合金經(jīng)600 ℃、6 h真空蠕變時效后屈服強度較冷鍛態(tài)下降幅度不大的原因是：彌散強化銅合金中納米彌散分布且高溫穩(wěn)定性好的Al2O3第二相粒子在較高溫度下對晶界、亞晶界具有強烈的釘扎效果，使彌散銅經(jīng)過蠕變時效后亞晶粒并未明顯長大。通過理論計算和實驗驗證，確定合金的主強化機制為亞結(jié)構(gòu)強化和第二相強化。
關(guān)鍵字: 銅合金；彌散強化；蠕變時效；亞晶界；力學(xué)行為
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Changsha Nanfang Tantalum Niobium Co., Ltd., Changsha 410133, China;
3. Science and Technology on High Strength Structural Materials Laboratory, Central South University, Changsha 410083, China;
4. State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China;
5. Key Laboratory of Non-ferrous Metal Materials Science and Engineering, Ministry of Education, Changsha 410083, China）
Abstract:The mechanical and electrical properties of the Cu-0.23%Al2O3 dispersion strengthened alloy treated with cold forging, annealing at 375 ℃ and creep aging at 600 ℃ for 6 hours after annealing at 375 ℃ were measured respectively. The microstructure and properties evolution were investigated by EBSD and TEM. The tensile strength, yield strength, elongation and electrical conductivity of the cold forged sample, which is also the primary sample, are 354 MPa, 345 MPa, 9.6% and 94.5%IACS, respectively. After the alloy is annealed at 375 ℃, the yield strength reduces by 1.7%, but the electrical conductivity only increases by 0.5%. After annealed at 375 ℃ and creep aged at 600 ℃ for 6 h, the yield strength of the alloy treated with creep aging at 600 ℃ for 6 h reduces by 9.6% and electrical conductivity increases by 1.6%, compared with the primary sample. The yield strength of creep aging alloy decreases slightly compared with that of the cold forging alloy, which attributes to the dispersion distribution nano-alumina particles with high temperature stability and effectively pinning the grain boundaries and sub-grain boundaries at high temperature. The main strengthening mechanism is sub-structure strengthening and dispersion strengthening.
Key words: copper alloy; dispersion strengthened; creep aging; sub-grain boundary; mechanical behavior
