Based on the analysis of the DSC thermograms, 50[degrees]C and 80[degrees] C were chosen as annealing temperatures for injection molded tensile bar
At present there is no method to relate quantitative measurements of porosity as collected on random metallographic cross sections to the maximum shrinkage pore size that might exist in the gage section of a tensile bar
. However, it is reasonable to assume that material with a higher porosity coverage would exhibit lower tensile ductility.
The metallic tensile bars
of AA 7075 aluminium alloy obtained after the melting and casting practices were prepared in accordance with the metallic tensile bar
sizes given in Table 2 and tensile bar
specimen given in Fig.
Caption: Figure 2: (a) Split-Hopkins tensile bar
(SHTB) testing system; (b) specimen for the tension test under high strain rate; (c) specimen fixed in the SHTB system.
Further studies will be conducted using state of the art foam injection molding technologies such as the core-back technique or gas counterpressure method to guarantee a constant foam structure in the cross section of the foamed tensile bar
over flow length.
The transducers were placed with clamps at the surface of the tensile bar
between the sensor arms of the extensometers (Figure 2).
samples were immersed in a 50% aqueous solution (by weight) of zinc chloride for 200 hr at 23 [+ or -] 2[degrees]C.
Furthermore, a jointed tensile bar
had to be constructed to join plates at either end of the Bar to counter a tendency to push out at either side.
Tensile ductility of high strength cast steel depends on porosity, specifically the largest pore size that may exist in the gage section of the tensile bar
. The relationship between quantitative metallographic measurement of porosity and tensile ductility can provide some guidance; for a steel with an ultimate tensile strength greater than 1790 MPa (260 ksi), porosity should be less than 0.04%.
After tensile tests, the morphology of the fractured tensile bar
surface of the various neat resins and blends was also examined using SEM.
Figure 3 shows a molded tensile bar
used for shape memory testing.