氮对Ti-6Al合金的铸态组织与性能的影响

采用熔铸工艺制备了w(N)=0.045~0.27%的原位自生氮化物增强钛铝基复合材料.分析测试了该材料的铸态组织和合金的力学性能.研究结果表明:在Ti-6A l的合金中,当w(N)=0.045~0.27%时,随着氮质量分数的增加,增强体的体积分数有所增加.Ti-6A l-xN中的氮化物较为细小.复合材料的硬度、抗压强度和弹性模量均高于Ti-6A l合金.随着氮质量分数增加材料的抗压强度、硬度和弹性模量增加.由压缩断口分析可知,基体为韧性断裂.随着氮质量分数增加,合金由韧窝 解理断口向具有解理特征的脆性断裂转变.

Effect of N on in-cast microstructure and mechanical properties of Ti-6Al alloys

Ti-6Al alloys containing nitrides of which N content(w(N)) was from 0.045% to 0.27% was fabricated by using in-situ melting-casting process.In-cast microstructure and the mechanical properties of the materials were studied.The results indicate that when w(N) of Ti-6Al was from 0.045% to 0.27%.The volume fraction of reinforcements is in direct ratio to w(N).The nitrides in Ti-6Al-N alloy were finer.The values of hardness,compressive strength and elastic modulus of titanium-aluminum matrix composites were higher than those of Ti-6Al alloys.With increasing of N content,the hardness,compressive strength and elastic modulus of titanium alloy increase.On the basis of analysis of SEM fractographies,matrix fracture is ductile.With increasing of N content,alloy fracture transforms into brittle fracture that has the characteristics of transgranular cleavage.