论文部分内容阅读
A 7mm-diameter ZrCu-based alloy rod,cast by fast cooling rate technology,is characterized with a gradient microstructure of ductile amorphous and ZrCu phases in the outer surface and brittle Zr2Cu and Cu10Zr7 phases in the center.Compressive mechanical tests at various strain rates illustrate the rate-dependent characteristics of yield stress and strain hardening after yielding.Post-test SEM observation and XRD analysis reveal the shearing,vein-like structuring,temperature-rise-induced melting,martensite transforming and lamellar cracking under the dynamic loading.A modified Johnson-Cook constitutive model was used to investigate the mechanisms of temperature-rise-induced softening at lower strain rate and martensite-transformation-induced hardening at higher strain rate,as well as the resultant phenomena of rate dependency.The mixed dynamic damage and fracture mechanisms of ductile and brittle models are discussed for the strength-toughness combination.Laminar cracking is addressed for developing a self-sharpening high-performance penetrator.