(山東科技大學(xué) 材料科學(xué)與工程學(xué)院，青島 266590)
摘 要: 利用直流電弧原位冶金技術(shù)制備粗晶碳化鎢塊體復(fù)合材料，并利用X射線衍射儀、電子探針等對(duì)其物相組成、微觀組織、W與C反應(yīng)過(guò)程和WC生長(zhǎng)形態(tài)演變機(jī)制進(jìn)行研究。結(jié)果表明：碳化鎢復(fù)合材料的主要硬質(zhì)相為WC和W2C；當(dāng)自耗電極長(zhǎng)度增加時(shí)，WC含量降低，但晶粒尺寸增大，最大晶粒尺寸約為100 μm。在原位冶金過(guò)程中，W和C元素通過(guò)溶解進(jìn)入熔池發(fā)生擴(kuò)散反應(yīng)，逐步形成W2C和WC。WC生長(zhǎng)形態(tài)由六棱柱演變?yōu)槿庵L(zhǎng)方式為小平面晶體臺(tái)階側(cè)向長(zhǎng)大；當(dāng)達(dá)到臨界過(guò)冷度時(shí)，WC晶粒迅速生長(zhǎng)。
關(guān)鍵字: 碳化鎢；復(fù)合材料；粗晶；直流電弧原位冶金；生長(zhǎng)形態(tài)
（College of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China）
Abstract:Coarse-grain bulk WC composites were prepared by direct current arc in-situ metallurgy. The examination of phase composition and microstructure for the materials, reaction process of W and C as well as transformation mechanism for WC morphologies was carried out by X-ray diffractometry and electron probe micro-analysis. The results show that WC and W2C are the main hard phases in the composites. Furthermore, the WC content decreases but the grain sizes of WC increase with increasing the length of consumable electrode, and the largest WC grains can reach about 100 μm. During the process of in-situ metallurgy, W and C dissolve and interdiffuse in the molten pool. As a result, W2C and WC form successively. The WC growth morphology is triangular prism that transforms from hexangular prism, and the growth pattern of WC is lateral growth layer by layer of the facet crystals. The WC grains can grow rapidly when undercooling reaches the critical value.
Key words: WC; composites; coarse-grains; direct current arc in-situ metallurgy; growth morphology
