(1. 內(nèi)蒙古工業(yè)大學 材料科學與工程學院，呼和浩特 010051；
2. 內(nèi)蒙古新材料工程技術(shù)中心，呼和浩特 010051)
摘 要: 采用原位反應近液相線鑄造法制備具有不同原位TiC顆粒含量的TiCp/7075鋁基復合材料，在7075鋁合金固−液兩相區(qū)間(477~635 ℃)的580和600 ℃進行二次加熱并保溫20 min，水淬固定其半固態(tài)組織，應用Image Pro Plus軟件測量平均晶粒尺寸及形狀因子，研究原位TiC顆粒含量對該合金二次加熱組織的影響。結(jié)果表明：當原位TiC顆粒質(zhì)量分數(shù)為0~4.4%時，隨著原位TiC顆粒質(zhì)量分數(shù)增加，合金鑄態(tài)組織直接轉(zhuǎn)變?yōu)榈容S晶組織，且在二次加熱過程中，原位TiC顆粒對晶粒的長大行為具有明顯的抑制作用；在相同的二次加熱條件下，4.4%TiCp/7075鋁基復合材料的平均晶粒尺寸比7075基體合金的減少30~40 μm，更加適合于半固態(tài)觸變成形。
關(guān)鍵字: 7075鋁合金；原位TiC顆粒；二次加熱；鑄造
（1. School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051, China;
2. Centre of Technology of New Materials Engineering, Inner Mongolia, Hohhot 010051, China）
Abstract:The TiCp/7075 Al matrix composites with different TiC particles contents were prepared by in-situ reactive near-liquidus casting, the sectioned specimens were reheated isothermally at 580 and 600 ℃ for 20 min in the two-phase (liquid+solid) region (477−635 ℃) of the near-liquidus casting 7075 alloy, then quenched in water. The grain size was measured by Image Pro Plus and the effect of in-situ TiC particles on the reheating structure was analyzed. The result shows that when the content of TiC particles is 0−4.4% (mass fraction), the in-situ TiC particles can not only keep near-liquidus casting 7075 alloy with finer and globular microstructure, but also control the grain growth evidently during reheating under the same condition. The average grain size of 4.4%TiCp/7075 Al matrix composites is 30−40 μm less than that of 7075 alloy, therefore it is more suitable for thixoforming.
Key words: 7075 Al alloy; in-situ TiC particle; reheating; casting
