热加工工艺对Ti-1300合金轧制棒材显微组织的影响

Effect of Heat Processing Technique on Microstructure of Ti-1300 Alloy

摘要:

研究了轧制温度、变形量以及热处理工艺对Ti-1300合金显微组织的影响，并讨论了热加工工艺与合金组织结构以及形貌之间的联系规律。结果表明：两相区轧制后的加工态Ti-1300合金主要由等轴的β相和球状α相组成，随轧制温度向合金相变点温度的升高，α相逐渐溶解在β基体上，因而β单相区轧制的合金主要由等轴的β相晶粒组成，而合金的晶粒随变形量的增加而破碎越充分，组织也更加细小、均匀。两相区固溶处理后的Ti-1300合金在晶界和晶间析出球状以及条状α相，弥散分布于亚稳定β基体，产生细晶强化效应，而β单相区固溶处理后的合金主要由平均晶粒尺寸为60 μm的等轴β相组成。两相区固溶处理后的时效态Ti-1300合金的组织主要由条状初生αp相、针状次生αs相以及β基体组成，热轧温度和变形量对时效态Ti-1300合金中αp相的形貌特征影响较小，但αp相和αs相都随时效温度的升高而不同程度的长大，针状次生αs相弥散分布在β基体上。

Abstract:

The effects of rolling temperature, deformation degree and heat treatment on the microstructure of Ti-1300 alloy were studied with an emphasis on the relationship between the heat processing technique and microscopic structure. The results show that Ti-1300 alloy with rolling temperature under β-transus temperature is composed of spherical α phase and equiaxed β phase, and α phase dissolves into β matrix with increasing of the rolling temperature. When the rolling temperature is increased to β-transus temperature or higher, the equiaxed β phase becomes the only dominant phase. The grains of Ti-1300 alloy with large deformation can be greatly refined, and the structure becomes homogeneous. After α+β phase region solution treatment, α phase with sphericity or strip shape precipitate in grain boundary and intergranular position and then disperse in metastable β matrix, and lead to dispersion strengthening and fine grain strengthening; however, the alloy after β phase region solution treatment is mainly composed of equiaxed β phase with the average grain size of about 60 μm. The Ti-1300 alloy after aging treatment is composed of strip αp phase, acicular αs phase and β matrix. There is few influence of the heat processing technique on the morphology parameters of αp phase in Ti-1300 alloy after aging treatment, but the morphology of αp and αs phase grow up with the aging temperature increasing. Acicular αs phase is dispersed on the β matrix.