Temperature effects on the strength and toughness of Be12Nb

This paper reports on strength and toughness of single-phase Be12Nb assessed at temperatures from ambient to 1200 C using four-point-bend and hardness tests. Vacuum-hot-pressed beryllide exhibits low bend strengths (∼110 MPa) and fracture toughness (∼2.5 MPa √m) at temperatures up to 500 C. Measured bend strength then increases to a maximum at 1000 C, while KIC slowly increases through 1100 C. Significant plastic deformation is only observed at 1200 C for the test strain rate of 2 x 10-6/s. Hardness values were found to remain relatively constant at temperatures up to 800 C and then sharply decrease at higher temperatures. Results indicate that low toughness limits bend strength at temperatures below ∼ 1000 C and prompts the observed increase in strength at high temperatures