Thermal Stability and Mechanical Properties of Nanocrystalline L1₂ Al₃Hf and (Al+12.5 at.%Zn)₃Hf Prepared by MA and SPS

Abstract:

Thermal stability and mechanical properties of L1₂ Al₃Hf and (Al+12.5 at.%Zn))₃Hf synthesized by mechanical alloying(MA) and spark plasma sintering(SPS) were investigated. Nanocrystalline L1₂ phase was produced after MA for 8 and 10 hrs in Al₃Hf and (Al+12.5 at.%Zn))₃Hf powders, respectively. The grain sizes were reduced to about 10 nm in both systems after MA for 20 hrs. After SPS, L1₂ phase was maintained only in Zn added system. In (Al+12.5 at.%Zn))₃Hf, L12 to D0₂₃ phase transformation was started at about 850°C and finished at about 1150°C Microhardness was decreased with increasing the annealing temperature while fracture toughness was increased due to the grain growth. Fracture toughness of (Al+12.5 at.%Zn))₃Hf was greater than that of Al₃Hf in all annealing temperatures. Fracture toughness of (Al+12.5 at.%Zn))₃Hf after annealing at 1200°C was about 5.38 MPam^1/2.

• Periodical: Materials Science Forum (Volumes 449-452)
• Pages: 809-812
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.449-452.809
• Online since: March 2004
• Authors: Chang Won Kang, Hee Sup Jang, Seon Jin Kim
• Keywords: Hafnium Trialuminide, Mechanical Alloying (MA), Nanocrystalline Intermetallics, Spark Plasma Sintering (SPS)

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