Impact ductility

The metallurgical experiments showed that the beta-alpha transition of the tin coating did not occur at irradiation doses of 3-5 Mrad and 6-7.5 Mrad at 5, —30, and —90°C and that the tensile properties, impact ductility, peel strength of soldered lap joints, and microstructure of commercial tinplate and solder were not affected by the irradiation conditions that are used in the sterilization of meat products. 

It is most convenient to classify metals by their lattice symmetry for low-temperature mechanical properties considerations. The fee metals and their alloys are most often used in the construction of cryogenic equipment. Aluminum, copper, nickel, their alloys, and the austenitic stainless steels of the 18-8 type are fee and do not exhibit an impact ductile-to-brittle transition at low temperatures. Generally, the mechanical properties of these metals im-... 

Strength in static bending, MPa Charpy impact ductility, kJm Rockwell hardness, scale M Shrinkage, cm/cm Water absorption, %... 

TaMe 3. Impact ductility versus type and length of fiber... 

Kochesfahani Sff, et al. Talc-TPO automotive formulations for low temperature impact ductility at —30° and —40°C. TPO Global Conference, conference proceedings. Society of Plastics Engineers 2008. 

Mechanical properties of the two types of PP axe listed in Table 21.4. Comparatively, the PP copolymer has lower stiffness and tensile strength, but higher impact ductility. These properties should facilitate the polymer to play the role of binder in the PP homo-polymer-PP copolymer composites. 

The steel ball projectiles were flattened or severely deformed or fragmented, depending on impact velocity, upon impacting the SiC/SiC composite. By contrast, the projectiles that impacted the oxide/oxide composite were neither flattened nor noticeably deformed even at the highest impact velocity of 400 m/s, as shown in Fig. 2. This was due to the oxide/oxide composite s soft and open structure, compared to the hard-and-dense SiC/SiC counterpart. Often at higher impact velocities > 300 m/s, steel ball projectiles were embedded into the oxide/oxide composite, similar to the case that sharp brittle particles impacted ductile metal targets. 

Examination of oven-aged samples has demonstrated that substantial degradation is limited to the outer surface (34), ie, the oxidation process is diffusion limited. Consistent with this conclusion is the observation that oxidation rates are dependent on sample thickness (32). Impact property measurements by high speed puncture tests have shown that the critical thickness of the degraded layer at which surface fracture changes from ductile to brittle is about 0.2 mm. Removal of the degraded layer restores ductiHty (34). Effects of embrittled surface thickness on impact have been studied using ABS coated with styrene—acrylonitrile copolymer (35). 

These steels are intended for use at liigh temperatures however, they may have low ductility and/or low impact properties at room temperature after being used above the temperature indicated by the single bar (I). 

Austenitic ductile iron, ASTM A571 4(3. No ad(htional requirements. 4b. Wel(hng not permitted. 4. The material shall be impact-tested. This material shall not be used at design minimum temperatures lower than —196 C (—320 F). Wel(hug is not permitted. 

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