(1. 河北省特種運(yùn)載裝備重點(diǎn)實(shí)驗(yàn)室(燕山大學(xué))，秦皇島 066004；
2. 先進(jìn)鍛壓成形技術(shù)與科學(xué)教育部重點(diǎn)實(shí)驗(yàn)室(燕山大學(xué))，秦皇島 066004)
摘 要: 基于高強(qiáng)鋁合金低溫形變熱處理工藝，研究了自然時(shí)效對(duì)AA7075鋁合金力學(xué)性能的影響并使用透射電鏡(TEM)對(duì)熱處理后的組織形貌進(jìn)行了觀察。將板材試樣單向拉伸與三維數(shù)字圖像相關(guān)(3D-DIC)技術(shù)相結(jié)合，研究了自然時(shí)效對(duì)板材拉伸變形鋸齒形屈服行為(Portevin-Le Chatelier，PLC效應(yīng))的影響，對(duì)B型、C型PLC效應(yīng)時(shí)域和空域行為的相關(guān)性進(jìn)行了研究；應(yīng)用輪廓掃描與3D-DIC等技術(shù)手段，研究了PLC效應(yīng)為對(duì)變形試樣表面質(zhì)量的影響機(jī)制。研究表明：隨自然時(shí)效時(shí)間延長(zhǎng)，PLC效應(yīng)產(chǎn)生的應(yīng)力鋸齒和PLC變形帶特征均由C型向B型轉(zhuǎn)變，直至消失；變形試樣表面波紋度減弱。對(duì)于PLC變形帶的帶靜態(tài)行為，變形帶作用位置隨機(jī)，產(chǎn)生周期短，對(duì)試件表面質(zhì)量的影響最大；帶動(dòng)態(tài)行為，PLC變形帶傳播引發(fā)板材表面質(zhì)點(diǎn)產(chǎn)生連續(xù)、均勻的厚向位移，對(duì)表面質(zhì)量影響小。
關(guān)鍵字: AA7075鋁合金；Portevin-Le Chatelier (PLC)效應(yīng)；時(shí)空演變；表面質(zhì)量
（1. Hebei Key Laboratory of Special Delivery Equipment, Yanshan University, Qinhuangdao 066004, China;
2. Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education of China, Yanshan University, Qinhuangdao 066004, China）
Abstract:Based on the low temperature thermo-mechanical treatment process of high-strength aluminum alloy, the uniaxial tensile test was combined with three-dimensional digital image correlation (3D-DIC) to study the effect of natural aging on the Portevin-Le Chatelier (PLC) effect of AA7075 sheet. The temporal and spatial evolutions of deformation in the full field of specimen surface of type B and type C were observed. Contour scanning and 3D-DIC were used to study the effect of PLC effect on the surface quality of deformed samples. The results show that with the extension of natural aging time, the serrations in the stress-strain curves and PLC bands characteristics generated by PLC effect change from type C to type B until disappear; at the same time, the surface waviness of the deformed sample weakens. For the static behavior of the PLC bands, the PLC bands has a random position and short production cycle, which has a great influence on the surface quality of the specimen. For the dynamic behavior of the PLC bands, the propagation of the PLC bands causes a continuous and uniform thick displacement of the sheet surface, which has little effect on the surface quality.
Key words: 7075 aluminum alloy; Portevin-Le Chatelier (PLC) effect; temporal and spatial evolutions; surface quality
