組織和力學(xué)性能的影響
(大連理工大學(xué) 材料科學(xué)與工程學(xué)院，鑄造工程研究中心，大連 116024)
摘 要: 研究電磁場(chǎng)和鈣微合金化對(duì)連鑄造過(guò)程中變形鎂合金微觀組織和力學(xué)性能的影響。利用金相顯微鏡(MEF-4A)、X射線衍射儀(XRD-6000)、掃描電鏡(JSM-5600LV)和電子探針(EPMA-1600)對(duì)制備的連鑄造錠微觀組織、相組成和元素分布進(jìn)行分析，并利用MTS NFW-810型試驗(yàn)機(jī)對(duì)連鑄造錠的力學(xué)性能進(jìn)行考察。結(jié)果表明：電磁場(chǎng)和鈣微合金化復(fù)合作用能連續(xù)鑄造出表面光滑、無(wú)氧化夾雜和偏析瘤的高質(zhì)量鑄錠，合金的微觀組織得到改善，施加電磁場(chǎng)和鈣微合金化后變形鎂合金AZ61連鑄錠具有晶粒細(xì)小、析出相彌散分布的均勻組織；電磁場(chǎng)和鈣微合金化均能提高變形鎂合金AZ61的抗拉強(qiáng)度，合金的最大抗拉強(qiáng)度值達(dá)到259.4MPa，較直冷連鑄AZ61鎂合金的提高24.2%；但鈣微合金化不利于提高AZ61鎂合金的伸長(zhǎng)率。
關(guān)鍵字: AZ61鎂合金；電磁場(chǎng)；微合金化；Ca
（School of Materials Science and Engineering, Foundry Research Center,
Dalian University of Technology, Dalian 116024, China）
Abstract:The continuous cast of wrought magnesium alloy AZ61 with or without electromagnetic field and microalloying of Ca was investigated. The microstructures and mechanical properties of the billets were analyzed by MEF-4A metallographic microscopy, XRD-6000 diffractometry, JSM-5600LV scanning electron microscopy, EPMA-1600 electron probe microanalyser and MTS NEW-810. The results show that the billets prepared by electromagnetic cast (EMC) and microalloying of Ca have smooth surface, and the defects, such as segregation and trapped oxide, on the billet surface can be eliminated. The microstructure is improved through applying electromagnetic cast (EMC) and microalloying of Ca，the refined grains and β-Mg17Al12 phases with small size are observed. The electromagnetic field and microalloying of Ca can improve the tensile strength, and the yield strength of AZ61 billet is 259.4MPa, increased by 24.2% compared with that of AZ61 billet by direct cold casting (DCC), but microalloying of Ca is disadvantageous to increasing the elongation of AZ61 magnesium alloy.
Key words: AZ61 magnesium alloy; electromagnetic field; microalloying; Ca
