Ductile solids

As we have seen, mobility of the molecules is one of the sources of ductility. However, if the mobility is obstructed by some barrier, an internal crack may form, and initiate crack propagation. In this way a ductile solid may become brittle. 

Properties Silver-white, ductile solid ((3 form). D 7.29 (20C), mp 232C, bp 2260C. Changes to brittle, gray (a) tin at temperature of 18C, but the transition is normally very slow. Soluble in acids and hot potassium hydroxide solution insoluble in water. Elemental tin has low toxicity, but most of its compounds are toxic. 

Properties Silvery-white ductile solid. D 6.11, mp 1900C, bp 3000C. Insoluble in water resistant to corrosion, but soluble in nitric, hydrofluoric, and... 

The CDM has two additional features that allow it to represent fracture in rocks. First, there is a brittle/ductile transition pressure. Above this pressure, the rock behaves as an elastic/plastic ductile solid, the failure surface is independent of the level of damage, and the damage is not allowed to increase, even if the failure surface is exceeded. Second, the CDM allows for non-vanishing plastic volume strain to approximate the dilatancy observed in certain laboratory experiments on oil shale. 

To overcome the above drawbacks, a new method based on essential work of fracture concept was introduced [Broberg, 1971, 1975]. In this method, it is proposed that when a cracked ductile solid, such as a toughened polymer blend is loaded, the fracture process and the plastic deformation take place in two different regions, viz. the inner process zone and the outer plastic zone. Much of the fracture work during crack propagation, dissipated in the plastic zone, is not directly associated with the fracture process. Only that work that goes into the fracture process zone is a material constant. Hence, the total fracture work, Wp should be separated into two parts, i.e., the essential work of fracture (i.e., the work required to create two new fracture surfaces, W),... 

PHYSICAL PROPERTIES bluish-black, amorphous powder or grayish-white lustrous metal soft, malleable, ductile solid hexagonal lattice below 865°C, body-centered cubic above 865°C may become embrittled by the absorption of nitrogen, oxygen, and carbon soluble in hot, very concentrated acids insoluble in water and cold acids MP (1857°C, 3375°F) BP (3577°C, 6471°F) DN (6.506 g/cm at 20°C) SG (6.51) CP (25.4 J/K-mol crystal at 25°C) VD (NA) VP (0 mmHg at 20 C) BHN (85). 

Physical Description Metal Soft, malleable, ductile, solid or gray to gold, amorphous poyirder. 

Figure 10.4 Schematic engineering stress ngineering strain (

Details Metallic cadmium is a soft, silvery and ductile solid. 

In the fracture of ductile solids, generally cracks grow by a mechanism whereby stresses and plastic strains concentrated in a process zone at the tip of a crack first produce some cavitation in the path of the erack at second-phase particles with... 

Properties Silvery-wh. ductile solid si. radioactive sol. in nitric, hydrofluoric, and cone, sulfuric acids insol. in water at.wt. 50.9414 dens. 6.11 m.p. 1900 C b.p. 3000 C resistant to corrosion Toxicology OSHA PEL TWA 0.05 mg(V205)/m (respirable dust and fume) LD50 (subcut., rabbit) 59 mg/kg poison by subcut. route irritant questionable carcinogen experimental tumorigen TSCA listed Precaution Flamm. in dust form from heat, flame, or sparks attacked by alkali, forming water-sol. vanadates violent reaction with BrFa, CI2, lithium, oxidants... 

Figure 10.11. Stress a versus strain e relationships for typical brittle or ductile solids. The asterisks indicate the fracture points. The triangles in the elastic regime, of fixed length in the strain, indicate the corresponding Young s moduli, Yh, Yd. The yield point of the ductile solid is characterized by the yield stress Uy and the yield strain Cy.

S. Suresh, Cyclic Deformation in Polycrystalline Ductile Solids, Fatigue of Materials, Cambridge University Press, 2001, p 86-131... 

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