(1. 北京科技大學(xué) 新金屬材料國(guó)家重點(diǎn)實(shí)驗(yàn)室，北京 100083；
2. 河海大學(xué) 力學(xué)與材料學(xué)院，南京 210098；
3. 常州市河海科技研究院有限公司，常州 213164)
摘 要: 采用熔體發(fā)泡法制備孔隙率為71.5%~72.5%、孔結(jié)構(gòu)均勻的泡沫Al-0.2Sc-0.17Zr合金。研究孔結(jié)構(gòu)、胞壁顯微組織以及等時(shí)時(shí)效對(duì)其壓縮和能量吸收性能的影響。結(jié)果表明：泡沫鋁合金的孔徑約為1 mm，且多呈球形；初生Al3(Zr，Sc，Ti)相具有層狀結(jié)構(gòu)，并能有效細(xì)化鑄態(tài)晶粒(尺寸約為50 μm)；在200~600 ℃等時(shí)時(shí)效過程中，泡沫試樣的壓縮性能隨溫度升高呈現(xiàn)先升高后下降的趨勢(shì)，325和425 ℃分別表現(xiàn)出由Sc和Zr大量析出引起的兩個(gè)明顯的強(qiáng)度峰；時(shí)效至425 ℃時(shí)試樣的能量吸收能力最強(qiáng)，且峰值時(shí)效附近的試樣能量吸收效率均得到提高，高效階段更持久；TEM實(shí)驗(yàn)結(jié)果表明，時(shí)效至425 ℃的泡沫鋁試樣胞壁中彌散分布著大量細(xì)小、共格的二次Al3(Sc，Zr，Ti)相，其粒徑為2.1~4.1 nm，這些相能釘扎晶界，阻礙位錯(cuò)運(yùn)動(dòng)，因而能顯著提高泡沫鋁合金的壓縮和吸能性能。
關(guān)鍵字: 閉孔泡沫鋁鈧鋯合金；壓縮性能；能量吸收；納米析出相
（1. State Key Laboratory for Advanced Metals and Materials,
University of Science and Technology Beijing, Beijing 100083, China;
2. School of Mechanics and Materials, Hohai University, Nanjing 210098, China;
3. Hohai Science & Technology Research Institute Co., Ltd., Changzhou 213164, China）
Abstract:Cellular Al-0.2Sc-0.17Zr foams with homogeneous pore structure and porosity of 71.5%-72.5% were fabricated by melt-foaming method. The effects of the pore structure, microstructure and isochronal aging on the compressive strength and energy absorption properties of the foams were investigated. The results show that the foams have homogeneous pore structure with pore size of about 1 mm. The primary Al3(Zr,Sc,Ti) phase with core/shell structure can refine the grain size to about 50 μm. The compressive strength first increases and then decreases during isochronal aging between 200 and 600 ℃. Two strength-peaks appear in the aging process at 325 and 425 ℃ due to the precipitation of Sc and Zr from the matrix, respectively. The isochronal aging is also beneficial to the improvement of energy absorption capacity and efficiency. The sample heat-treated at 425 ℃ shows the best energy absorption capacity, and the high energy absorption efficiency stages for all the samples around the peak aging are prolonged. The TEM observation of the cell wall at 425 ℃ confirms the precipitation of nano-size Al3(Sc,Zr,Ti) particles that are coherent with Al matrix with a radius of 2.1-4.1 nm. This suggests that these Al3(Sc,Zr,Ti) particles can inhibit the grain boundary sliding and dislocation movement, thus, strengthening the cell walls and increasing the compressive strength and energy absorption properties of the foams.
Key words: cellular Al-Sc-Zr alloy; compressive property; energy absorption; nano-size precipitate
