本文關(guān)鍵詞： 鎂合金 凝固 冷卻速率 異質(zhì)形核 晶粒長(zhǎng)大　出處：《中國(guó)有色金屬學(xué)報(bào)》2017年02期 　論文類(lèi)型：期刊論文

【摘要】：采用銅模噴鑄與高溫退火相結(jié)合,研究快冷AZ91+Si C合金組織細(xì)化與高溫晶粒長(zhǎng)大,揭示Si C顆粒對(duì)亞快速凝固鎂合金異質(zhì)形核及熱穩(wěn)定性的影響。結(jié)果表明:Si C可促進(jìn)亞快速凝固過(guò)程中異質(zhì)形核,阻礙凝固界面遷移,顯著細(xì)化噴鑄合金組織。400℃等溫退火后,組織從枝晶向等軸晶轉(zhuǎn)變并發(fā)生明顯晶粒長(zhǎng)大,快冷AZ91合金保溫8 h后平均晶粒尺寸達(dá)78μm。添加2%Si C后,晶粒長(zhǎng)大得到有效控制,8 h退火處理后平均晶粒尺寸僅為22μm。Si C的存在提高了基體中晶格畸變,退火組織中析出層片狀與粒狀共存的沉淀相。晶粒細(xì)化及Si C的添加提高了快冷鎂合金顯微硬度。隨退火時(shí)間延長(zhǎng),合金硬度下降。沉淀相的析出導(dǎo)致AZ91+2%Si C合金硬度增加,最高可達(dá)111HV,比AZ91合金的硬度提高63.2%。
[Abstract]:The microstructure refinement and high temperature grain growth of fast cooling AZ91 sic alloy were studied by means of copper mold spray casting and high temperature annealing. The effect of sic particles on the heterogeneous nucleation and thermal stability of subrapid solidified magnesium alloy is revealed. The results show that: sic can promote heterogeneous nucleation during subrapid solidification, hinder the transfer of solidification interface, and refine the microstructure of spray casting alloy after isothermal annealing at .400 鈩，

本文編號(hào)：1522906