(中南大學(xué) 粉末冶金國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)沙 410083)
摘 要: 采用噴霧干燥−熱還原的方法制備納米級(jí)93W-4.9Ni-2.1Fe復(fù)合粉末，并以其為原料制備出含0.03%Y2O3(質(zhì)量分?jǐn)?shù))的細(xì)晶鎢合金，研究微量稀土摻雜對(duì)燒結(jié)致密化和顯微組織的影響以及93W-4.9Ni-2.1Fe合金在動(dòng)態(tài)壓縮狀態(tài)下的力學(xué)行為。結(jié)果表明：納米級(jí)復(fù)合粉末在1 380~1 410 ℃之間液相燒結(jié)可實(shí)現(xiàn)材料的近全致密化，比同種成分的傳統(tǒng)鎢合金的燒結(jié)溫度降低了120 ℃左右，合金的相對(duì)密度可達(dá)99%以上，且合金的晶粒尺寸為5 µm左右。與傳統(tǒng)W-Ni-Fe合金相比，細(xì)晶W-Ni-Fe合金在高應(yīng)變率下具有更高的合金強(qiáng)度和延性，同時(shí)，在較低應(yīng)變率下有形成局部絕熱剪切帶的傾向；添加微量Y2O3能進(jìn)一步提高細(xì)晶W-Ni-Fe合金的絕熱剪切敏感性，有利于在較低應(yīng)變率下形成絕熱剪切帶。
關(guān)鍵字: Y2O3；細(xì)晶；93W-4.9Ni-2.1Fe合金；動(dòng)態(tài)力學(xué)性能；絕熱剪切帶
its dynamic failure behavior
（State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:Fine-grain (FG) 93W-4.9Ni-2.1Fe alloy containing 0.03%Y2O3(mass fraction) was obtained via liquid phase sintering of nano-composite powders prepared by spray drying, subsequent thermal reduction process. The influence of Y2O3 on sintering behavior and microstructure and the dynamic mechanical properties and dynamic failure were studied. The results show that the near full densification is realized and the finer spherical-shape tungsten grains with the size of about 5 mm in the alloy are obtained during liquid phase sintering in the range from 1 380 ℃ to 1 410 ℃, which is 120 ℃ lower than that of the traditional tungsten heavy alloys, and the relative density of the alloy reaches over 99%. Compared with traditional tungsten heavy alloys, the fine-grain tungsten heavy alloy possesses higher yield strength and larger elongation at high strain rate, and promotes the tendency to adiabatic shear band (ASB) formation at lower strain rate. On the basis mentioned above, adding Y2O3 can further increase the sensitivity of ASB of fine-grain W-Ni-Fe alloy, which is more beneficial to form obvious ASB at lower strain rate.
Key words: Y2O3; fine-grain; 93W-4.9Ni-2.1Fe alloy; dynamic mechanical properties; adiabatic shear band
