Biomedical Engineering Reference
In-Depth Information
Available are several popular Co-based medical alloys. They
include:
vitallium, protasul-2, protasul-10, protasul-21 WF (Table
3.11), endocast, MP35N (Table 3.12). Mechanical properties and
corrosion resistance of cobalt-base alloys are function of chemical
compositions of Co-base materials and their microstructures
(Tables 3.13 and 3.14).
Ta b l e 3
.
11
Chemical composition of protasul-21 WF [wt %]
Cr Mo Co Ni Fe C Si Mn W N
26
−
30 5
−
7 bal <1 <0,75 <0,35 <1 <1 <0,2 <0,25
Ta b l e 3
.
12
Chemical composition of MP35N [wt %]
Cr Mo Co Ni Fe C Si Mn Ti B
,
SP
19-21 9-10 bal 33-37 1.0 0.03 0.01 0.15 1.0 0.01 0.015
Alloying theory as used in alloy development or design relates
the properties of the alloys to their chemical compositions and
microstructures [85, 120, 123]. A required property is obtained
by selection of suitable chemical compositions and fabrication
processes (e.g., melting, casting, forming and heat treatment) to
obtain the desired microstructures. For biomedical materials, such
as dental and joint implant materials, corrosion resistance, and
mechanical properties (e.g., strength, ductility and work-ability, etc.)
are of prime importance for optimum clinical performances [120].
Ta b l e 3
.
13
Mechanical properties of MP35N alloy
Properties
Comments
Hardness, Rockwell B 90
Annealed
Tensile strength, Ultimate 896 MPa
Annealed
Tensile strength, Yield 379 MPa
0.2% YS; Annealed
Elongation at break
65.0 %
Annealed; in 4D
Reduction of area 75.0 %
Modulus of elasticity 232.8 GPa
234.8 GPa
201.0 GPa
Temperature 482°C
201.3 GPa
Temperature 482°C
Annealed
Cold Worked and Aged
Annealed
Cold Worked and Aged
Shear modulus
67.8 GPa
Cold Worked and Aged; at
482°C
70.60 GPa
Annealed; at 482°C
80.94 GPa
Cold Worked and Aged; at 78°F
83.36 GPa
Annealed; at 78°F
