摘要：Al-B中間合金是一種良好的細(xì)化劑，在熔煉鋁時(shí)可以細(xì)化晶粒，但是Al-B合金中AlB2通常是粗大的長條狀，導(dǎo)致細(xì)化能力受到限制。本文以Al-B中間合金作為研究對(duì)象，對(duì)Al-B中間合金進(jìn)行等通道擠壓（ECAP），研究經(jīng)1、2、4、6、8變形道次后Al-B中間合金的顯微組織、顯微硬度、電導(dǎo)率的變化，以及將ECAP變形Al-B中間合金作為細(xì)化劑添加到純鋁中，并觀察不同道次的Al-B中間合金對(duì)純鋁的細(xì)化效果。研究結(jié)果表明：隨著擠壓道次的增加，Al-B中間合金的顯微組織由粗大的長桿狀逐漸破碎為細(xì)小的顆粒狀。Al-B合金的顯微硬度經(jīng)等通道變形后明顯增加，由鑄態(tài)的31.02Hv增加到2道次時(shí)的50.38Hv，4道次后有所降低，但是變化不大，趨于穩(wěn)定。Al-B中間合金的電導(dǎo)率隨著擠壓道次的增加逐漸下降。

　　　純鋁的宏觀組織大多為粗大的柱狀晶，中心等軸晶較少且比較粗大。加入ECAP變形Al-B合金后，中心等軸晶區(qū)逐漸擴(kuò)大且晶粒細(xì)小，粗大的柱狀晶區(qū)縮小且變細(xì)。加入6道次ECAP變形Al-B合金后，中心等軸晶區(qū)最大，晶粒最細(xì)小。隨著Al-B合金變形道次的增加，顯微硬度逐漸增大，但是8道次時(shí)，顯微硬度較低。不同道次ECAP變形Al-B合金細(xì)化的純鋁的電導(dǎo)率呈現(xiàn)波動(dòng)性變化。

關(guān)鍵詞：ECAP；Al-B中間合金；顯微組織；性能；細(xì)化效果

Abstract:Al-B master alloy is a good refiner, it can refine aluminum grains in the aluminum melting. In Al-B master alloy, AlB2 is usually a long rod-shaped, so its refining ability is limited. In present work, Al-B master alloy is used for studying. After equal channel angular pressing (ECAP), the material microstructure, mechanical properties, and the conductivity of Al-B master alloys were studied, and observed the refinement. The results show that the microstructure of Al-B master alloy is gradually broken by the thick long rod-shaped small granular with the increase of ECAP passes. After equal channel deformation, the hardness of Al-B master alloy increase obviously, increased by 31.02Hv for the cast to 50.38Hv for 2 pass, then reduce after 4 pass, but little change in the stabilized. The conductivity of the Al-B master alloy is decreasing with the increase of ECAP passes.

     The microstructures of pure aluminum are mostly coarse grains, the equiaxed grains in the center are less and thick. After adding Al-B master alloy, the range of equiaxed grains expand and the grains are small. The range of coarse columnar grains reduces and the grains become thinner. When adding ECAP Al-B master alloy of 6 pass, the range of equiaxed grains is the largest and the grains are smallest. With the increase of ECAP passes, the hardness of Al-B master alloy gradually increase, but the hardness of 8 pass is lower. The refinement of the Al-B master alloys after different deformations changes without regularity.

Keywords: ECAP; Al-B master alloy; microstructure; properties; refinement