(1. 南昌大學(xué) 材料科學(xué)與工程學(xué)院，南昌 330031；2. 南昌大學(xué) 機電工程學(xué)院，南昌 330037)
摘 要: 將剪切低溫澆注半固態(tài)(LSPSF)漿料制備工藝與傳統(tǒng)高壓鑄造工藝銜接，研究出一種半固態(tài)漿料直接成形工藝——流變壓鑄技術(shù)。結(jié)果表明：LSPSF工藝可在15~20 s制備出初生α(Al)形狀因子為0.93，晶粒尺寸為70 μm且分布均勻，初生α(Al)內(nèi)部沒有夾裹液相的YL112鋁合金半固態(tài)漿料；與傳統(tǒng)壓鑄相比，流變壓鑄可改善YL112合金鑄件的微觀組織，半固態(tài)漿料在二次凝固中發(fā)生體積凝固，鑄件微觀組織細小且分布均勻。該LSPSF流變鑄造工藝與傳統(tǒng)壓鑄工藝銜接簡便，半固態(tài)漿料輸送平穩(wěn)，具有較強的可操作性。
關(guān)鍵字: 流變成形；半固態(tài)；微觀組織；壓鑄；YL112鋁合金
（1. School of Materials Science and Engineering, Nanchang University, Nanchang 330031, China;2. School of Mechanical and Electronic Engineering, Nanchang University, Nanchang 330031, China）
Abstract:A new one-step semi-solid processing technique, the rheo-diecasting (RDC) process, was exploited, in which the independently developed low superheat pouring with a shear field (LSPSF) process was combined with the existing cold chamber high pressure diecasting (HPDC) process. The experimental results show that the LSPSF can prepare sound semi-solid secondary diecasting aluminum alloy YL112 slurry in 15−20 s to fully meet the production rate of HPDC, the primary α(Al) presents in mean equivalent diameter of 70 μm and shape factor of 0.93 and features zero-entrapped eutectic. Compared with conventional HPDC process, RDC process can improve microstructures in castings. Secondary solidification of semi-solid slurry takes place uniformly throughout the entire cavity and produces an extremely fine and uniform microstructure. The advantages of the present RDC process include easy incorporation into existing HPDC machine without infrastructure changes, smooth transportation of semi-solid slurry from the LSPSF machine to the shot chamber, high operability for pouring temperature and thermal control.
Key words: rheoforming; semi-solid; microstructure; diecasting; YL112 aluminum alloy
