AUTHOR=Duong Binh N. , Do Binh T. , Dang Dung D. , Tran Huy D. TITLE=Fabrication and hardness of in-situ Al3Ti–Al2O3 composite JOURNAL=Frontiers in Materials VOLUME=10 YEAR=2023 URL=https://www.frontiersin.org/journals/materials/articles/10.3389/fmats.2023.1265903 DOI=10.3389/fmats.2023.1265903 ISSN=2296-8016 ABSTRACT=

In this work, an in-situ Al₃Ti–Al₂O₃ composite was optimally synthesized from raw powders via mechanical milling and conventional sintering processes. The strong influence of milling time on the promotion of the phase reaction between the initial TiO₂ and Al materials was proven by using X-ray diffraction and surface morphology analysis. The obtained results showed that the milling process did not initiate any reaction between the raw TiO₂ and Al materials. However, the milling process was important for creating a homogeneous powder mixture and refining the particle size of the powders. The Al₃Ti–Al₂O₃ composites were completely formed after conventional sintering at 750°C for 30 min for a milling time of over 4 h. The highest obtained microhardness of the composite was approximately 130 HV, which was suggested to be related to the microstructure of the bulk composite specimen consisting of two main phases, the Al₃Ti matrix and the Al₂O₃ particles dispersed in the matrix. A small portion of an unidentified phase, a Ti-rich compound, was found in the matrix together with a tiny fraction of AlTi₃. We suggest that the optimal sintering process and mechanical milling are important key factors in fabricating bulk hardness Al₃Ti–Al₂O₃ composite materials.