Thermal Mechanical Processing Effects on Microstructure Evolution and Mechanical Properties of the Sintered Ti-22Al-25Nb Alloy
Abstract
:1. Introduction
2. Materials and Methods
3. Results and Discussion
3.1. Tensile Behaviors
3.2. Microstructure Characterization
3.3. Fracture Toughness and Fracture Mechanism Analyses
4. Conclusions
- The sintered Ti-22Al-25Nb alloy was processed by isothermal forging. The microstructure was homogenous compared to the as-sintered alloy. The morphology of O phase changed from the coarse lath O to the lamellar O and acicular O. The distribution of O phase was relatively homogeneous.
- While the sintered alloy was processed by isothermal forging, the tensile strength and elongation increased from 340 MPa, 3.6% to 500 MPa, 4.2%, respectively. In addition, the fracture toughness (KIC) was enhanced from 7 to 15 MPa·m−1/2.
- Judging by the fractography observations, a typical embrittlement fracture consisting of cleavage and quasi-cleavage fracture was developed. The morphologies of O phase within B2 phase had a key effect on improving strength and ductile. The fracture mechanism changing from cleavage fracture to quasi-cleavage fracture mainly resulted from morphologies and the distribution of O phase. Meanwhile, the interfaces in the transformed O/B2 colony, not the grain size, predominantly controlled fracture toughness in the Ti-22Al-25Nb alloy.
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Wang, Y.; Lu, Z.; Zhang, K.; Zhang, D. Thermal Mechanical Processing Effects on Microstructure Evolution and Mechanical Properties of the Sintered Ti-22Al-25Nb Alloy. Materials 2016, 9, 189. https://doi.org/10.3390/ma9030189
Wang Y, Lu Z, Zhang K, Zhang D. Thermal Mechanical Processing Effects on Microstructure Evolution and Mechanical Properties of the Sintered Ti-22Al-25Nb Alloy. Materials. 2016; 9(3):189. https://doi.org/10.3390/ma9030189
Chicago/Turabian StyleWang, Yuanxin, Zhen Lu, Kaifeng Zhang, and Dalin Zhang. 2016. "Thermal Mechanical Processing Effects on Microstructure Evolution and Mechanical Properties of the Sintered Ti-22Al-25Nb Alloy" Materials 9, no. 3: 189. https://doi.org/10.3390/ma9030189