Role of Si on lamellar formation and mechanical response of two SPS Ti-15Al-15Si and Ti-10Al-20Si intermetallic alloys
Role of Si on lamellar formation and mechanical response of two SPS Ti-15Al-15Si and Ti-10Al-20Si intermetallic alloys
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DOI：
10.1016/j.intermet.2021.107099
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发表时间：
2021-01-16
期刊：
影响因子：
4.4
通讯作者：
Paoletti, C.
中科院分区：
文献类型：
--
作者：
Cabibbo, M.;Knaislova, A.;Paoletti, C.
采用放电等离子烧结（SPS）技术制备了两种不同Si含量的TiAlSi金属间化合物，并对其进行了纳米压痕、韧性和耐磨性测试。用透射电镜分析了两种合金的显微组织差异，并提出了强化模型。基于显微组织的强化模型与由纳米压痕硬度得到的合金应力吻合较好。结果表明，随着Si含量的增加，TiAl相开始形成片层组织和片层间孪晶。Al减少有利于等量的Si被发现稍微促进Ti 5Si 3硅化物的形成和最终的TiAl相粗化。Ti-15 Al-15 Si合金具有亚微米等轴晶组织。另一方面，Ti-10Al-20 Si合金的特征在于片状TiAl相，这被认为是导致两种合金不同力学响应的原因。
Two TiAlSi intermetallic compounds produced by Spark Plasma Sintering (SPS) adding different Si content were tested by nanoindentation, toughness and wear resistance. Microstructure differences between the two alloys were characterized by TEM and a strengthening model was proposed. The microstructure-based strengthening model well agreed with alloys stress obtained from the nanoindentation hardness. It resulted that as Si content increases, the TiAl phase started to form lamellar structure and inter-lamellar twinning. Al reduction in favour of an equal amount of Si was found to slightly promote Ti5Si3 silicide formation and eventually a TiAl phase coarsening. Ti-15Al-15Si alloy showed submicrometric equiaxed TiAl grains. On the other hand, Ti-10Al-20Si alloy was characterized by a lamellar TiAl phase which was identified as responsible for the different mechanical responses of the two alloys.