Formability of a high-strain-rate superplastic Al–4.4Cu–1.5Mg/21SiCW composite under biaxial tension

Advances in anisotropy and formability

“…Brunet and Clerc [62] have extended Hora's model by including the strain rate sensitivity exponent and used it for studying the influence of that parameter on the limit strains. Chan [77] has developed a model of forming limits prediction for the superplastic forming. Predictive models of localized necking for strain-rate-dependent sheet metals have been developed by Mattiasson et al [209,210], Zhang et al [313], Jie et al [155].…”

High-strain-rate superplastic gas pressure forming of an Al–4.4Cu–1.5Mg/21SiCW composite under variable strain rate paths

“…Superplasticity is known to be accompanied by cavitation, and extensive cavitation leads to premature failure or to degradation of the mechanical properties of post-formed components. It was reported that the parameter of the cavity growth rate of the HSRS Al-4.4Cu-1.5Mg/21SiC W composite is dependent on its stress state [10]. The experimental limit strains of the composite at different stress ratios were also determined, and the major limit strain was found to increase with the stress ratio.…”

“…The surface strain distributions of the gas pressure formed diaphragms were obtained by measuring the grid circles under an optical microscopy, whereas the thickness strain of the diaphragms was determined using a ball point gauge. The volume fraction of cavities was determined using both the image analyzing technique and the density measurement technique [10]. The thickness distribution of the formed product is found to be uneven.…”

“…Although a considerable amount of research has been conducted on gas pressure forming of conventional superplastic materials, there has been relatively less effort to study the deformation and cavitation behavior of HSRS materials in biaxial tension, not to mention the effect of variable strain rate paths. Superplastic gas pressure forming of HSRS Al-MMCs has been explored in Al7475/SiC p [7], Al6061/20SiC W [8], Al2009/SiC W [9], and Al-4.4Cu-1.5Mg/21SiC W [10]. It was reported that an Al6061/20SiC W hemispherical dome had been successfully gas pressure formed in 17 s at an applied flow stress of 4 MPa and at 873 K. It is known that uniformity of thickness is one of the key factors affecting the formability of superplastic materials and the quality of the formed articles.…”

“…The deformation and cavitation behavior of a HSRS Al-4.4Cu-1.5Mg/21SiC W composite under different biaxial stress states has recently been investigated using a gas pressure bulging tester [10]. The composite was bulged using dies with different aspect ratios at an optimum condition determined from the superplastic tensile test.…”