Dynamic Compression Behavior of a Mg–Gd-Based Alloy at Elevated Temperature

Dynamic Compression Behavior of a Mg–Gd-Based Alloy at Elevated Temperature

The dynamic compression behavior and microstructure evolution at 400 °C of an extruded Mg–8Gd–4Y–Nd–Zr alloy withdifferent tempers were investigated. The peak-aged samples exhibit the highest compressive strength, followed by as-extrudedsamples and over-aged samples. The highest dynamic compressive strength of 582 MPa was achieved by peak-aged samplecompressed at 1224 s−1. The high strength was attributed to the formation of abundant thermally stable βʹ precipitates andsome dynamic precipitates. The dynamic compressive strength of peak-aged sample and over-aged sample is not sensitiveto strain rates, while that of the as-extruded sample is sensitive to strain rates. The dynamic compressive strength of the asextrudedalloy can reach 535 MPa when compressed at 2024 s−1. The high strength was mainly ascribed to the formationof numerous dynamic precipitates and the work hardening effect caused by dislocations. The cracks are composed of crackthat is 45° to loading direction on the cylindrical surface and crack on the compressed surface. Microstructure observationindicates that the crack was easily propagated along the interface between the adiabatic shear band and matrix, grainboundaries. The equilibrium phase β in over-aged sample was unable to hinder the crack propagation.

The dynamic compression behavior and microstructure evolution at 400 °C of an extruded Mg–8Gd–4Y–Nd–Zr alloy withdifferent tempers were investigated. The peak-aged samples exhibit the highest compressive strength, followed by as-extrudedsamples and over-aged samples. The highest dynamic compressive strength of 582 MPa was achieved by peak-aged samplecompressed at 1224 s−1. The high strength was attributed to the formation of abundant thermally stable βʹ precipitates andsome dynamic precipitates. The dynamic compressive strength of peak-aged sample and over-aged sample is not sensitiveto strain rates, while that of the as-extruded sample is sensitive to strain rates. The dynamic compressive strength of the asextrudedalloy can reach 535 MPa when compressed at 2024 s−1. The high strength was mainly ascribed to the formationof numerous dynamic precipitates and the work hardening effect caused by dislocations. The cracks are composed of crackthat is 45° to loading direction on the cylindrical surface and crack on the compressed surface. Microstructure observationindicates that the crack was easily propagated along the interface between the adiabatic shear band and matrix, grainboundaries. The equilibrium phase β in over-aged sample was unable to hinder the crack propagation.