Amorphous ductility

Yielding in Amorphous Ductile Polymers. Typical amorphous ductile polymers are PVC and PC. Deformation at room temperature results in the... 

Fig. 43. Campositioii ranges for the formation of the amorphous phase, and the changes of and in (a) Al-Y-Ni and (b) Al-Ce-Ni systems. Double open circle, amorphous (ductile) open circle, amorphous (brittle) semi-open circle, amorphous plus crystalline solid circle, crystalline. The asterisk represents 7",.

PCTFE plastic is compatible withHquid oxygen, remains ductile at cryogenic temperatures (16—22), and retains its properties when exposed to either uv or gamma radiation. PCTFE exhibits a refractive iadex of 1.43 (ASTM D542) and an amorphous sheet can provide over 90% transmittance. 

Maybe produced as rapidly soHdified, ductile. amorphous/microcrystalline foil. ... 

Ultem PEI resins are amber and amorphous, with heat-distortion temperatures similar to polyethersulfone resins. Ultem resins exhibit high modulus and ate stiff yet ductile. Light transmission is low. In spite of the high use temperature, they are processible by injection mol ding, stmctural foam mol ding, or extmsion techniques at moderate pressures between 340 and 425°C. They are inherently flame retardant and generate Httie smoke dimensional stabiUties are excellent. Large flat parts such as circuit boards or hard disks for computers can be injection-molded to maintain critical dimensions. 

Strength Fibrous minerals Ductility gaining tensile strength. Carbon fibers are more expensive fibrous minerals are least expensive but only slightly reinforcing. Reinforcement makes brittle resins tougher and embrittles tough resins. Fibrous minerals are not commonly used in amorphous resins. 

Deflection Temperature (HDT) Fibrous minerals Ductility yield much greater increases in HDT than do amorphous resins. As with tensile strength, fibrous minerals increase HDT only slightly. Fillers do not increase HDT. 

Poly(Dat-Tyr-Hex carbonate) is a slowly degrading, strong and ductile material. This material may be applicable in situations where a mechanical support function is needed for an extended period of time such as in small bone fixation devices (bone pins or screws). The reproducible fabrication of such devices by injection molding is particularly easy due to the amorphous character of poly(Dat-Try-Hex carbonate). 

Our principal concern is often the polymer s mechanical properties. For instance, the requirements of the handle of an electrician s screwdriver are very different from those of wire insulation. In the former application, we are free to choose stiff polymers of many types, including glassy amorphous polymers. In contrast, wire insulation must be flexible, which limits our choice to ductile polymers. 

PET can be blended with PBT or polycarbonate (PC) to make blends or alloys. Polycarbonate is a high Tg (150 °C) ductile, high-impact-strength polymer but has rather poor solvent resistance because of its amorphous nature. PET/PC blends have therefore proved advantageous because they combine the solvent-resistance... 

Physical Form. The metal is soft, ductile, silver-white, electropositive cadmium oxide may take the form of a colorless amorphous powder or red or brown crystals. 

The alloys are first produced by rapid solidification and are amorphous in nature. They are either directly fabricated as powders, by a process such as high-pressure gas atomisation (HPGA), or by melt-spinning of ribbons, which are subsequently pulverised to form a powder (<150 /im). The powders are then consolidated by hot extrusion between 950-1050°C where the initial amorphous structure breaks down and forms a fine dispersion of stable borides in a ductile Fe-based matrix. 

They consist of metallic (such as of brass) containers filled with an expl chge which has a resistance of 10-200 ohms and which fires in 10-100 msec upon passage of an electric current of 100 to 500 thousand ergs. One of the preferred expl compns is fine LA 70 elec conducting powd (consisting essentially of amorphous C graphite) 30%. For use with fasteners of low ductility ca 8% heat-sensitive expl diluent such as Tetra-... 

In terms of the mechanical behavior that has already been described in Sections 5.1 and Section 5.2, stress-strain diagrams for polymers can exhibit many of the same characteristics as brittle materials (Figure 5.58, curve A) and ductile materials (Figure 5.58, curve B). In general, highly crystalline polymers (curve A) behave in a brittle manner, whereas amorphous polymers can exhibit plastic deformation, as in... 

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