In situ fabrication of α-Al 2O 3 and Ni 2Al 3 reinforced aluminum matrix composites in an Al–Ni 2O 3 system

• Published in: Advanced powder technology : the international journal of the Society of Powder Technology, Japan Vol. 22; no. 5; pp. 629 - 633
• Main Authors: Zhu, Heguo, Ai, Yinglu, Li, Jianliang, Min, Jing, Chu, Da, Zhao, Jun, Chen, Jie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2011
• Subjects: Chemical synthesis; Composites; Differential scanning calorimetry (DSC); Thermodynamic properties; X-ray diffraction; X-ray diffraction; Composites; Differential scanning calorimetry (DSC); Chemical synthesis; Thermodynamic properties
• ISSN: 0921-8831; 1568-5527
• DOI: 10.1016/j.apt.2010.09.016

α-Al 2O 3 ceramic particles and Ni 2Al 3 intermetallic compound reinforced aluminum matrix composites were successfully fabricated via exothermic dispersion (XD) reaction in an Al–Ni 2O 3 system. Thermodynamic analysis indicated that the reaction between Al and Ni 2O 3 could occur spontaneously due to its negative Gibbs free energy. The reaction characteristic was discussed by using X-ray diffraction (XRD) method and differential scanning calorimetry (DSC) analysis. The results showed that the reactions of the Al–Ni 2O 3 system consisted of two steps as following: (1) the Al firstly reacted with Ni 2O 3 to form the stable α-Al 2O 3 particles and active Ni atoms; (2) the active Ni atoms further reacted with Al to form Ni 2Al 3. The values of activation energy of the two step reactions were around 457.3 and 282.4 kJ/mol, respectively. The scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS) revealed that the Ni 2Al 3 blocks were uniformly distributed throughout the matrix, while the α-Al 2O 3 particles were slightly segregated in the matrix. The strength of the composite is controlled by the strength of Ni 2Al 3 phase, and the tensile strength and the elongation rate of the composite with 30 vol.% reinforcement volume fraction are 210 MPa and 8%, respectively.