Microstructure and Mechanical Properties of TiAl Alloys Consolidated by Spark Plasma Sintering from Elemental Powders

Lu Dahai; Liu Xinwang; Sun Rui; Fan Zitian

doi:10.15980/j.tzzz.2018.05.025

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Microstructure and Mechanical Properties of TiAl Alloys Consolidated by Spark Plasma Sintering from Elemental Powders
Vol. 38, Issue 5, Pages: 551-555(2018)
Published： 2018 ，
DOI： 10.15980/j.tzzz.2018.05.025

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[1]卢大海,刘鑫旺,孙锐,樊自田.元素粉末法SPS烧结固化TiAl合金的组织和力学性能[J].特种铸造及有色合金,2018,38(05):551-555.

Lu Dahai, Liu Xinwang, Sun Rui, et al. Microstructure and Mechanical Properties of TiAl Alloys Consolidated by Spark Plasma Sintering from Elemental Powders. [J]. Special Casting & Nonferrous Alloys 38(5):551-555(2018)
[1]卢大海,刘鑫旺,孙锐,樊自田.元素粉末法SPS烧结固化TiAl合金的组织和力学性能[J].特种铸造及有色合金,2018,38(05):551-555. DOI： 10.15980/j.tzzz.2018.05.025.

Lu Dahai, Liu Xinwang, Sun Rui, et al. Microstructure and Mechanical Properties of TiAl Alloys Consolidated by Spark Plasma Sintering from Elemental Powders. [J]. Special Casting & Nonferrous Alloys 38(5):551-555(2018) DOI： 10.15980/j.tzzz.2018.05.025.

摘要

以元素粉末为原料

通过放电等离子烧结（SPS）分别合成了Ti-46Al-9Nb-0.5Si和Ti-46Al-2Cr-0.5Si-0.2C。研究了各种SPS条件下合金元素扩散及微观组织的演变规律。在1 300℃×5min及以上条件下

Ti、Al、Si和C元素能够均匀扩散

Cr几乎完全扩散

仅有很少的富集区

而Nb的扩散远未完成。两组合金均表现为典型的层片晶团加γ相的双相组织。提高烧结温度和时间

层片晶团的数量和晶粒尺寸增加。各种条件下SPS烧结获得的试样压缩强度在1 200

350MPa之间

增加层片晶团含量能提高强度

但因烧结温度和时间的增加引起的晶粒粗化会导致强度下降。室温下的压缩性能与铸造热处理的试样及SPS预合金化粉末获得的材料的性能相当。

Abstract

Two sets of TiAl alloys

Ti-46 Al-9 Nb-0.5 Si and Ti-46 Al-2 Cr-0.5 Si-0.2 C

were synthesized and consolidated by spark plasma sintering from elemental powders as raw materials.The elemental diffusion and evolution of microstructure with various SPS conditions were investigated.The uniform diffusion of Ti

Si and C can be realized at/above 1 300 ℃×5 min.The diffusion of Cr can almost completed with few enrichment regions.However

the diffusion of Nb can’t be realized.The two alloys exhibit typical duplex microstructure with lamellar colonies andγphase.The amount of lamellar colonies and grain size are increased with the increase of sintering temperature and holding time.The compressive strength is in range of 1 200 MPa to 1 350 MPa under the SPS conditions.More lamellar colonies lead to a higher strength

however

the coarsening of grains caused by higher temperature and longer duration can reduce the strength.The room temperature compressive properties are comparable to the previous values obtained from casting plus heat treatment and SPSed pre-alloyed powders.