Surface finish Tensile strength

The forgings were evaluated by density, microstructure, surface finish, tensile strength, notched impact strength, ductility, and fatigue strength measurements... 

Properties. Properties of stmctural siHcon nitride ceramics are given in Table 2. These values represent available, weU-tested materials. However, test methodology and the quaHty of the specimens, particularly their surface finish, can affect the measured values. Another important material property is tensile strength. Values obtained on Norton s NT154 material are 750 MPa at RT, 500 MPa at 1200°C, and 350 MPa (50,000 psi) at 1400°C (62). 

Rubber Particle Size and Dispersion. Particle size is important for impact. If the size distribution is wide—i.e., 1-20 microns—the large particles represent a less efficient use of the toughness of the rubber and tend to reduce tensile strength and to give poorer surface finish when compared with a narrow particle size distribution—i.e., 1-5 microns (4). 

Ni-AI Bronze. Cast Ni-Al bronze has been friction stir processed (FSP), as reported by Ref 26. Yield strength of the FSP material (420 MPa, or 61 ksi) was more than double that of the cast alloy (193 MPa, or 28 ksi). Tensile strength also increased substantially due to the processing (700 MPa compared with 420, or 102 ksi compared with 61). However, elongation dropped to 14%, compared with 20% in the as-cast material. Surface finish and tool life were both excellent. In addition to the improvement in as-cast properties, FSP was demonstrated to reduce or eliminate internal porosity due to casting defects. 

Mainly used in TPs, mica reinforcement improves the tensile and flexural strength and flexural modulus. Heat distortion temperature is increased and the coefficient of linear thermal expansion is reduced. Shrinkage and creep are significantly reduced, and warpage is virtually eliminated. Chemical resistance is high and permeability is reduced. Mica can also help to produce a Class A surface finish (Table 2.11). 

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