金属の機械的性質（Mechanical Properties of Metals）
・弾性率； Modulus of elasticity
/ Strength is the ability of a material to resist the externally applied forces without breaking or yielding. The internal resistance offered by a part to an externally applied force is called stress.
Elasticity is the property of a material to regain its original shape after deformation when the external forces are removed.
The machinability of a material can be measured in a number of ways such as comparing the tool life for cutting different materials or thrust required to remove the material at some given rate or the energy required to remove a unit volume of the material.
When a part is subjected to a constant stress at high temperature for a long period of time, it will undergo a slow and permanent deformation called creep.
The hardness is usually expressed in numbers which are dependent on the method of making the test.
A Textbook of Machine Design R.S. Khurmi et al. EURASIA PUBLISHING HOUSE (PVT.) LTD. 2005