(1. 中國兵器科學(xué)研究院 寧波分院，寧波 315103；
2. 江麓機(jī)電集團(tuán)有限公司，湘潭 411100)
摘 要: 利用萬能試驗(yàn)機(jī)和Hopkinson拉桿(SHTB)對7A62鋁合金進(jìn)行了準(zhǔn)靜態(tài)和動(dòng)態(tài)拉伸性能測試，研究該合金室溫及高溫塑性流動(dòng)應(yīng)力動(dòng)態(tài)響應(yīng)特征，結(jié)合OM、SEM、TEM、DSC、LFA等測試對該合金的物理性能及原始微觀組織進(jìn)行分析。結(jié)果表明：7A62鋁合金在大量高密度細(xì)小沉淀析出物粒子及亞微米級高熔點(diǎn)平衡析出粒子復(fù)合強(qiáng)化作用下，準(zhǔn)靜態(tài)屈服強(qiáng)度可達(dá)608 MPa。在室溫動(dòng)態(tài)變形過程中，該合金應(yīng)變率強(qiáng)化效應(yīng)顯著。隨著應(yīng)變率高于684 s-1時(shí)，合金屈服強(qiáng)度對應(yīng)變率敏感性顯著增強(qiáng)。在1100 s-1、25~500 ℃條件下，合金表現(xiàn)出溫度敏感性的沉淀強(qiáng)化相回溶及動(dòng)態(tài)再結(jié)晶的熱軟化效應(yīng)，500 ℃高溫動(dòng)態(tài)屈服強(qiáng)度超過200 MPa。在動(dòng)態(tài)力學(xué)性能變化規(guī)律的基礎(chǔ)上，建立了7A62鋁合金的Johnson-Cook(J-C)本構(gòu)模型。
關(guān)鍵字: 7A62鋁合金；高強(qiáng)度；動(dòng)態(tài)力學(xué)行為；Johnson-Cook模型
（1. Ningbo Branch of China Academy of Ordnance Science, Ningbo 315103, China;
2. Jianglu Machinery Electronics Group Co., Ltd., Xiangtan 411100, China）
Abstract:In order to study the dynamic response of plastic flow stress of 7A62 aluminum alloy at room temperature and high temperature, the quasi-static and dynamic tensile mechanical properties of 7A62 aluminum alloy were investigated by using universal testing machine and a Split Hopkinson Tensile Bar (SHTB). The physical properties and initial microstructure of the alloy were analyzed by OM, SEM, TEM, DSC and LFA. The results show that the quasi-static yield strength of 7A62 aluminum alloy can reach 608 MPa under the combined strengthening of numerous fine precipitates with high density and sub-micron high melting point equilibrium particles. The strain rate strengthening effect of the alloy is remarkable during dynamic deformation at room temperature. When the strain rate is higher than 684 s-1, the yield strength of the alloy is larger sensitive to the strain rate. At strain rate of 1100 s-1 and temperature of 25-500 ℃, the alloy shows some sensitivity to temperature due to thermal softening effect of the re-solution of strengthening precipitates and the dynamic recrystallization. And the dynamic yield strength exceeds 200 MPa at 500 ℃. The Johnson-Cook (J-C) constitutive model of 7A62 aluminum alloy was established based on the dynamic mechanical properties.
Key words: 7A62 aluminum alloy; high strength; dynamic mechanical behavior; Johnson-Cook model
