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Title: Evaluation of in situ mechanical properties of composites by using nanoindentation techniques

Journal Article · · Acta Metallurgica et Materialia; (United States)
; ;  [1];  [2]
  1. Univ. of Minnesota, Minneapolis (United States). Dept. of Chemical Engineering and Materials Science
  2. 3M Co., St. Paul, MN (United States)

The in situ mechanical properties of the fibers, matrices and interfaces in an Al[sub 2]O[sub 3] fiber-reinforced [beta]-21S Ti alloy have been evaluated by using two nanoscale indentation tests. The Al[sub 2]O[sub 3] fibers were coated with a refractory metal and Y[sub 2]O[sub 3] duplex coating which served as a diffusion barrier during the HIPing used to produce the metal matrix composites. The hardness of the fibers, interfaces and matrix were obtained by performing a series of indentations across the fiber/matrix interface. The hardness decreases from the Al[sub 2]O[sub 3] fiber to the Ti matrix. Additionally, by doing fiber pushout tests, the interfacial shear strength, interfacial frictional stress and mode 2 interfacial fracture energy were obtained. Scanning electron microscopy and X-ray mapping were used for microstructural and chemical analysis. The mechanical properties of the interfaces were related to their chemical composition. The interfacial fracture was found to occur at the interface between the refractory metal and the Y[sub 2]O[sub 3]. The mode 2 interfacial fracture energy in this system is more than two orders of magnitude lower than the interfacial fracture energy of Ti/Al[sub 2]O[sub 3] without the diffusion barrier.

OSTI ID:
5149377
Journal Information:
Acta Metallurgica et Materialia; (United States), Vol. 42:3; ISSN 0956-7151
Country of Publication:
United States
Language:
English