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1、材料力学性能（Mechanical properties of materials）1 elastic deformation: material deformation after loading, unloading this part of the deformation disappeared, the material returned to the original state of nature.2 plastic deformation: the adjacent part of a microstructure causes permanent displacement wi
2、thout causing material to rupture.3 elastic limit: the stress of elastic deformation is excessive to the elastic plastic deformation (yield deformation).4 modulus of elasticity: engineering is called the stiffness of materials and represents the resistance of materials to elastic deformation. The es
3、sence is to produce the stress required for 100% elastic deformation.5: fast anelastic loading or unloading, additional materials and properties of elastic strain with time of the.6 internal friction: the deformation energy absorbed by material is greater than that of unloading when it is loaded, th
4、at is, some deformation work times absorb material, and the work absorbed in this part is called internal friction of material.7 toughness: the ability to absorb plastic deformation work and fracture work before fracture.8 superplasticity: under certain conditions, presents a very large elongation (
5、about 1000%) without necking and fracture.9 dimple: microscopic fracture of micropore aggregation fracture.10 coefficient of stress state: ratio of maximum shear stress to normal stress in materials under different loading conditions.11 shear modulus: the ratio of torque to shear strain during torsi
6、on.12 notch sensitivity: the ratio of tensile strength to tensile strength of notched specimens. NSR13 hardness: a characterization of the degree of hardness of materials. The ability of a material surface to resist deformation or rupture in a certain volume.14 stress field strength factor: the para
7、meter that reflects the stress field intensity at the crack tip.15 fracture toughness: when the stress field strength factor increases to a critical value, the material with cracks breaks down, and the critical value is called fracture toughness.16 low stress brittle fracture: when the material has
8、macro cracks, the brittle fracture occurs when the stress level is not high or even lower than the yield limit.17 creep: metal under constant temperature and constant load slow plastic deformation phenomenon.18 creep limit: resistance index of plastic material to plastic deformation under high tempe
9、rature and long time load.19 lasting strength: at the specified temperature, to reach the specified experimental time without breaking stress value.20 stress relaxation: the stress in a metallic material decreases with time during a given temperature and initial stress.21: two for rolling contact fa
10、tigue of materials or rolling and sliding friction, alternating contact stress makes the long-term effect of surface fatigue wear, fatigue local small or small pieces of material and produce spalling.1 elastic specific work: the ability of metal materials to absorb elastic deformation work. Generall
11、y, the maximum elastic deformation work expressed by unit volume before plastic deformation starts with metal.2. is: metal materials fast loading in elastic range or after unloading, with the extension of time to produce additional strain phenomenon known as anelasticity, is behind the phenomenon of
12、 stress strain.3. cycle toughness: the ability of materials to absorb non inverting forms of work is called cyclic toughness.4. Bauschinger effect: metal materials after pre loading produces a small amount of plastic deformation after unloading, loading in the same direction, the provisions of resid
13、ual stress increase; the reverse loading, the provisions of residual stress decrease.FiveCleavage facets: this cleavage plane, roughly in size, is called cleavage facets.6. plasticity: the ability to produce irreversible permanent (plastic) deformation before fracture of a metal material.Toughness:
14、the ability to absorb plastic deformation, work, and fracture prior to fracture of a metallic material.7. cleavage step: when the cleavage crack meets the screw dislocation, a high B step is formed.8. river pattern: a mark of cleavage steps.9.: the cleavage plane is the metal material under certain
15、conditions, when the applied stress reaches a certain value, at a very fast rate along certain crystallographic plane transgranular fracture and fracture, because marble is similar, so the crystallographic plane for solving theory.10. transgranular fracture: transgranular fracture through the crysta
16、l can be ductile fracture or brittle fracture.Intergranular fracture: the crack propagates along grain boundaries, most of which are brittle.11. ductile brittle transition: when a metal material with a certain toughness is under a certain temperature point, the impact absorption work decreases obviously, and the fracture mode changes from the original ductile
