(1. 重慶大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400044；
2. 重慶大學(xué) 國家鎂合金工程技術(shù)研究中心，重慶 400045)
摘 要: 考察熱軋工藝及隨后熱處理對Mg-Y-Nd合金組織演變的影響。結(jié)果表明：低溫(＜500 ℃)軋制時，大量稠密析出相的出現(xiàn)致使軋制性能極大地降低且組織難以細化；在固溶溫度下軋制(525 ℃)時，晶粒極易粗化；當(dāng)軋制溫度略低于固溶溫度時，軋制過程中會析出彌散的第二相粒子。這些粒子的存在沒有惡化軋制性能且有效地釘扎晶界并抑制高溫下再結(jié)晶晶粒的粗化。該合金的較佳軋制工藝如下：軋制溫度為500 ℃、每道次軋制變形量為10%且總軋制變形量70%。熱軋后，材料獲得平均晶粒尺寸為30 μm左右的組織，并產(chǎn)生較強的基面織構(gòu)。固溶處理1 h可有效地消除位錯并維持細晶和基面織構(gòu)。進一步增加固溶時間，晶粒發(fā)生粗化且織構(gòu)變得分散。相比于均勻化態(tài)，經(jīng)T6處理的熱軋態(tài)Mg-Y-Nd合金的屈服強度提高176 MPa。
關(guān)鍵字: Mg-Y-Nd合金；熱軋；熱處理；顯微組織；織構(gòu)
（1. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China;
2. National Engineering Research Centre for Magnesium Alloys, Chongqing University, Chongqing 400045, China）
Abstract:The effects of hot-rolling and the following heat treatment on microstructure were investigated. The results show that, for rolling below 500 ℃, the dense precipitates are formed, which is bad for further rolling and grain refinement. However, rolling at the solution temperature (525 ℃), the recrystallization grains grow rapidly and coarsen. When rolling temperature is slightly lower than the solution temperature, dispersion particles are precipitated, which are not harmful for further rolling and are capable of pinning grain boundary to resist coarsening of recrystallization grains at high temperature. The better rolling processing parameters are that the rolling temperature is 500 ℃, the thickness reduction per pass is 10% and the total thickness reduction is 70%. After hot-rolling, the fine and uniform microstructure with an average size of approximately 30 μm and a strong basal texture are obtained. The solution treatment for 1h can effectively eliminate dislocation and retain the same grain size and texture. As solution time further increases, the grain coarsens and texture becomes dispersive. Compared to the as-received alloy, the yield strength of the hot-rolled Mg-Y-Nd alloy with T6 treatment is increased by 176 MPa.
Key words: Mg-Y-Nd alloy; hot-rolling; thermal treatment; microstructure; texture
