In-situ Ti-6Al-4V/TiC composites synthesized by reactive spark plasma sintering: processing, microstructure, and dry sliding wear behaviour
In-situ Ti-6Al-4V/TiC composites synthesized by reactive spark plasma sintering: processing, microstructure, and dry sliding wear behaviour
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DOI：
10.1016/j.wear.2019.202944
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发表时间：
2019-08-15
期刊：
影响因子：
5
通讯作者：
Inkson, Beverley J.
中科院分区：
文献类型：
--
作者：
Bai, Mingwen;Namus, Righdan;Inkson, Beverley J.
采用低能球磨法制备了碳化钛(TiC)增强钛基复合材料(TMCs)。采用石墨片作为碳源，作为润滑剂，在混合过程中帮助粉末流动。在混合过程中，石墨转变为纳米碳微晶，有利于后续SPS过程中TiC第二相的快速生成。复合材料表现出一种新颖的蜂窝状组织，在钛的α/β基体中形成了5-6个体积分数的TiC亚微米细小颗粒。此外，纳米硬度为12.4 Gpa的TiC相的增强提高了母体合金的耐磨性(5.1 Gpa)，在与Si3N4球的干往复滑动试验中，磨损率降低了26-28%。在滑动过程中，磨屑(主要是锐钛矿型二氧化钛)堆积在隆起的TiC硬质相上，形成附着氧化物的阻挡层，保护下面的合金基质免受磨损和氧化，从而降低磨损率。
Titanium carbide (TiC) reinforced Titanium Matrix Composites (TMCs) have been synthesized via an in-situ reactive spark plasma sintering (SPS) process using commercial Ti-6Al-4V spherical powders pre-coated with 1 wt% carbon nanoparticles by low-energy ball milling. Graphite flakes are used as carbon source, which aids powder flow during mixing as lubricant. Graphite transforms to nano-crystallite carbon during mixing which is favourable for the rapid formation of TiC second phase in the following SPS process. The composites exhibited a novel honeycomb-like cellular microstructure with the formation of 5-6 vol% fine TiC submicron grains interconnected in the titanium alpha/beta matrix. In addition, the reinforcement of the TiC phase with a nano-hardness of 12.4 GPa, improves the wear resistance of the parent alloy matrix (5.1 GPa), with a reduction of 26-28% in wear rate during dry reciprocating sliding tests against Si3N4 balls. During sliding, the wear debris (predominantly anatase TiO2) builds up on the raised TiC hard phase forming a barrier layer of adhered oxide that can protect the alloy matrix underneath from abrasion and oxidation, leading to a reduced wear rate.