What is brittleness and toughness of materials? What is the difference between elasticity and plasti

Under the action of impact and vibration loads, the property that the material can absorb a large amount of energy and produce a certain deformation without destruction is called toughness or impact toughness. Construction steel (mild steel.

Wood, plastic, etc. are more typical ductile materials. Pavement, bridges, crane girders.

and structures with seismic requirements should consider the toughness of the material. Brittleness refers to the property that when the external force reaches a certain limit, the material will be suddenly damaged without warning, and there is no obvious plastic deformation during failure. Mechanical properties of brittle materials.

It is characterized by compressive strength.

Much greater than tensile strength.

The ultimate strain value at the time of failure is extremely small. Brick, stone, ceramics, glass, concrete, cast iron, etc. are all brittle materials. Compared to ductile materials, they are quite disadvantageous for resisting impact loads and bearing vibrations.

Under the action of external force, when the external force reaches a certain limit, the material is suddenly damaged, and there is no obvious plastic deformation when it is broken, this property is called brittleness, and the material with this property is called brittle material. Brittle materials have much higher compressive strength than tensile strength and are less resistant to shock or vibration loads. Such as brick, stone, concrete, ceramics, cast iron, etc. are brittle materials.

Under the action of shock and vibration loads, the material can absorb a large amount of energy, and at the same time, it can also produce a certain plastic deformation without destroying the property called toughness (or impact toughness). Construction steel, wood, etc. are ductile materials. Ductile materials have large plastic deformation before fracture, and plastic materials have tensile and compressive capabilities.

Same. Generally, it is used as a tensile member, and is also suitable for forgings, cold-worked parts, and impact parts. The deformation of brittle materials before fracture is small, and the compressive capacity is much stronger than the tensile ability, so it is suitable for compressive members.

Brittle materials are materials that are broken and broken under the action of external forces (such as tension, impact, etc.) with only a small deformation. Commonly used brittle materials are cast iron, ceramics, stone, glass, etc. Mild steel.

It is a plastic material. Cast iron is a brittle material. Plastic materials are materials that are not destroyed under the action of external forces, although they produce significant deformation. Commonly used plastic materials are steel, copper, aluminum alloy and so on.

Under the action of external forces (such as tensile, impact, etc.), the material only produces a small deformation, that is, the property of breaking is broken. Polymer brittleness is related to the polymer structure and use conditions (temperature, external force action rate, etc.), and the flexible chain polymer has low brittleness and good toughness. Rigid chain polymers are the opposite. The brittle materials in building materials refer to bricks, tiles, stones, concrete, glass, etc., which are characterized by high compressive strength, but should not withstand tensile force, will not produce plastic deformation after stress, and are brittle fracture when damaged; Ductile materials, also known as plastic materials, are characterized by high tensile strength, but plastic deformation will occur after being stressed, such as:

Rebar. When using, they should give full play to their respective characteristics as much as possible, and use bricks, stones, and concrete under pressure; Reinforcement for bearing tension, bending, and shear forces.

Many mechanical components or parts are often subjected to shock loads during use. Such as rock drills, forging machinery, rolling mills, train bridges, etc. They are subjected to an impact force that acts for a short period of time and at a certain speed.

In this case, the ability of the material to resist the impact load is called the toughness of the material, also known as the impact toughness. Impact load is a dynamic load, and the stress that a member is subjected to under an impact load is called impact stress, which is much greater than the stress experienced under static load. The damaging effect of shock loads on mechanical parts or components is also much more dangerous than static loads.

Impact load is essentially an energy load, and the index of the material's ability to resist the impact load is not expressed in terms of stress, but in terms of absorbed energy (impact energy).

1. Elasticity refers to the property that the material is completely restored to its original state after the external force is canceled. Plasticity refers to the property that the material is deformed after being deformed by force, and the material remains in the state after the deformation is canceled by the external force.

2. Brittleness refers to the property of sudden failure of the material when it is stressed to a certain extent. Toughness refers to the ability of a material to absorb energy under the action of impact and resist breakdown.

3. The brittle material does not undergo obvious deformation from the force to the time it is destroyed, and the material with toughness will absorb the external force when it is subjected to external force to produce large deformation, and it must have been greatly deformed when it is destroyed.

Hardness, a physical term, is the ability of a material to resist a hard object pressing into its surface locally is called hardness. The local resistance of solids to the invasion of external objects, comparing the indicators of softness and hardness of various materials. There are different hardness standards due to the different test methods specified.

The mechanical meanings of various hardness standards are different and cannot be directly converted to each other, but they can be compared through experiments.

Brittleness refers to the property that the material only produces a small deformation under the action of external forces (such as tensile, impact, etc.), that is, fracture failure, contrary to toughness, until there is only a small elastic deformation without plastic deformation before fracture. Brittle materials have poor resistance to dynamic loads or impacts. The brittleness of a metal material depends mainly on its composition and microstructure.

Brittle material: Mu block is a Xunhuai Hu material that only produces bright and small deformation under the action of external force, that is, it is destroyed and broken. Commonly used brittle materials are cast iron, ceramics, stone, glass, etc.

Polymer brittleness is related to the polymer structure and use conditions such as temperature, external force action rate, etc., and the flexible chain polymer has low brittleness and good toughness. Rigid chain polymers are the opposite.

Answer]: A hint is as follows: The difference between brittleness and toughness is that there is no or obvious deformation before the broken aber, and the energy absorbed by the force is low or high.

a.Yield Limit.

b.Strength limit.

c.The limit of proportions is a loss.

d.Elastic limit.

Correct Answer: Strength Limit.