Ti含量对Nb-Si-Mo-Ti系合金组织性能的影响

Effect of Ti Content on Microstructure Properties of Nb-Si-Mo-Ti Alloy

为研究Ti含量对Nb-Si系合金组织及性能的影响,以机械球磨和SPS烧结技术结合的方法制备了Nb-16Si-10Mo-x Ti(x=0,2,4,6,8,10)合金,对x不同时的合金在室温、1200℃时的组织及力学性能进行探究。结果表明:Ti含量增多,Ti ss韧性相逐渐增多并聚集,组成相包括Nb ss、Nb 5 Si 3和Ti ss相。室温下,合金弯曲强度、断裂韧性等有所提高,硬度下降,抗压强度先降后增,x=0时,抗压强度最高为2300 MPa,而Nb-Si-Mo-Ti系合金抗压强度最高为2200 MPa,且断裂方式由脆性断裂转变为复合断裂。1200℃下,抗压强度先降后增,x=0时,最高为605 MPa,随Ti含量增加,Nb-Si-Mo-Ti系合金抗压强度最高可达470 MPa,同时有较好塑韧性。1200℃压缩后,组织细化,韧性相沿垂直于压缩方向拉长,硬脆相则被挤压到韧性相内部或表面分布。

The effect of Ti content on the microstructure and properties of Nb-Si alloy was studied.Nb-16Si-10Mo-x Ti(x=0,2,4,6,8,10)alloy was prepared by means of mechanical ball milling and SPS sintering technology.The microstructure and mechanical properties of alloys with different x at room temperature and 1200℃were investigated.The results show that as the content of Ti increases,the ductile phase of Ti ss gradually increases and gathers,and the constituent phases include Nb ss,Nb 5Si 3 and Ti ss phases.At room temperature,the bending strength and fracture toughness of the alloy increase,the hardness decreases,and the compressive strength decreases first and then increases.When x=0,the maximum compressive strength is 2300 MPa.The highest compressive strength of Nb-Si-Mo-Ti alloy is 2200 MPa,and the fracture mode changes from brittle fracture to composite fracture.At 1200℃,the compressive strength decreases first and then increases.When x=0,the highest compressive strength is 605 MPa.With the increase of the Ti content,the highest compressive strength of the Nb-Si-Mo-Ti alloy can reach 470 MPa,and it has good plastic toughness.After compression at 1200℃,the microstructure is refined,the toughness phase is elongated perpendicular to the compression direction,and the hard and brittle phase is extruded to the interior or surface of the toughness phase.