[15P-T21-09] MIM and Heat Treatment of NiTi Superelastic Alloys
キーワード：Functional Materials, Shape Memory Alloys, Gas quenching
Tensile test specimens have been produced by metal injection moulding of pre-alloyed powders. Different thermal posttreatments as water quenching, gas quenching and ageings have been performed and the resulting mechanical performances have been compared. The specimens have been characterized by tensile tests, optical and scanning electron microscopy, DSC and XRD analysis.
SEM observation reveals that the oxide layer thickness in gas quenched parts is less than 1 μm, which is clearly below the one observed in water quenched parts (~10 μm). In addition, XRD analysis show that the gas quenched material is free of Ni4Ti3
precipitates. The subsequent thermal ageing results in the precipitation of Ni4Ti3, which strenghtens the alloy and influences the superelastic plateau.
Tensile tests show that the thermal treatment of gas quenching followed by aging.
SEM observation reveals that the oxide layer thickness in gas quenched parts is less than 1 μm, which is clearly below the one observed in water quenched parts (~10 μm). In addition, XRD analysis show that the gas quenched material is free of Ni4Ti3
precipitates. The subsequent thermal ageing results in the precipitation of Ni4Ti3, which strenghtens the alloy and influences the superelastic plateau.
Tensile tests show that the thermal treatment of gas quenching followed by aging.