3. Metal matrix composites

Metal-matrix composites (MMCs) are a class of materials that are usually made by reinforcing conventional metallic matrix using high-performance second phase constituents. Metal-matrix composites MMCs can be tailored to improve different properties such as strength, stiffness, thermal conductivity, and corrosion, wear, creep resistance. In general, metal-matrix composites (MMCs) can be produced by stir casting, squeeze casting and powder metallurgy.

Magnesium matrix composites can be fabricated by using different reinforcements to obtain different characteristics. For example, Mg2Si/Mg composites have a mechanical strength that is comparable to that of industrial magnesium cast alloys (AZ63) but with a damping capacity that is 100 times higher [34]. Carbon nanotubes (CNTs) can be used as reinforcements with magnesium [35] or its alloys

Figure 12. The effect of different volume fractions of SiCp on the stress-life curve of AZ91D magnesium metal matrix composite [41, 42].

### Fatigue of Magnesium-Based Materials DOI: http://dx.doi.org/10.5772/intechopen.85226

such as AZ31, AZ91, ZK60 and AZ61 to improved their ultimate tensile strength, yield strength and modulus of elasticity composite [36]. Different reinforcements such as aluminum oxide particulate Al2O3 [37], nickel particles [38] or nano-size Y2O3 particles [39] have been tested with magnesium and its alloys and found to yield different results.

Fatigue behavior of magnesium AZ91 can be improved by adding ceramic reinforcements [40]. In addition, the elastic modulus, yield strength and ultimate tensile strength of AZ91 can be increased using SiCp particles as discontinuous reinforcements. Figures 12 and 13 show the effects of two different reinforcements

Figure 13.

3. Metal matrix composites

Figure 11.

Figure 12.

54

composite [41, 42].

fluids "SBF" [11].

stir casting, squeeze casting and powder metallurgy.

Metal-matrix composites (MMCs) are a class of materials that are usually made by reinforcing conventional metallic matrix using high-performance second phase constituents. Metal-matrix composites MMCs can be tailored to improve different properties such as strength, stiffness, thermal conductivity, and corrosion, wear, creep resistance. In general, metal-matrix composites (MMCs) can be produced by

Comparison between the stress life curves for biodegradable AZ91D tested in air and different simulated body

Magnesium - The Wonder Element for Engineering/Biomedical Applications

Magnesium matrix composites can be fabricated by using different reinforcements to obtain different characteristics. For example, Mg2Si/Mg composites have a mechanical strength that is comparable to that of industrial magnesium cast alloys

nanotubes (CNTs) can be used as reinforcements with magnesium [35] or its alloys

The effect of different volume fractions of SiCp on the stress-life curve of AZ91D magnesium metal matrix

(AZ63) but with a damping capacity that is 100 times higher [34]. Carbon

The effect of different volume fractions of Saffil alumina fibers on the stress-life curve of AZ91D magnesium metal matrix composite [40].

#### Figure 14.

Comparison of stress-strain curves of the dual particle reinforced magnesium alloy (AZ31 + Al2O3 + Ni) with the unreinforced matrix alloy (AZ31) cyclically deformed at room temperature (T = 25°C) at R = 0.1 and � 1.0 [38].

on the stress-life curve of magnesium AZ91D. These figures show that fatigue life at a given stress amplitude can be increased by adding proper volume fraction of the reinforcements.

References

[1] von Mises R. Mechanik der plastischen Formänderung von Kristallen. ZAMM-Journal of Applied Mathematics and Mechanics/Zeitschrift für Angewandte Mathematik und Mechanik. 1928;8(3):161-185

Fatigue of Magnesium-Based Materials DOI: http://dx.doi.org/10.5772/intechopen.85226

> properties of T5-treated ZK60 alloy. Materials Transactions. 2009;50(4):

[11] Sajjad J, Singh Raman RK, Davies CHJ. Corrosion fatigue of a magnesium alloy in modified simulated body fluid. Engineering Fracture

[12] Ya U et al. Corrosion fatigue of extruded magnesium alloys. Materials Science and Engineering: A. 2003;360

[13] Gu XN et al. Corrosion fatigue behaviors of two biomedical Mg alloys— AZ91D and WE43—in simulated body fluid. Acta Biomaterialia. 2010;6(12):

[14] ASTM-E606/E606M-12, Standard Test Method for Strain-Controlled Fatigue Testing. West Conshohocken,

[15] Albinmousa J, Jahed H, Lambert S. Cyclic axial and cyclic torsional behaviour of extruded AZ31B magnesium alloy. International Journal of Fatigue. 2011;33(11):

[16] Roostaei AA, Jahed H. Role of loading direction on cyclic behaviour characteristics of AM30 extrusion and its fatigue damage modelling. Materials Science and Engineering: A. 2016;670:

[17] Yu Q et al. An experimental study on cyclic deformation and fatigue of extruded ZK60 magnesium alloy. International Journal of Fatigue. 2012;

[18] Yu Q et al. Multiaxial fatigue of extruded AZ61A magnesium alloy. International Journal of Fatigue. 2011;

Mechanics. 2015;137:2-11

(1-2):132-139

4605-4613

PA, USA; 2012

1403-1416

26-40

36(1):47-58

33(3):437-447

791-798

[2] Albinmousa J. Multiaxial fatigue characterization and modeling of AZ31B magnesium extrusion [PhD thesis]. Waterloo, Ontario in Canada: University of Waterloo; 2012

Terminology Relating to Fatigue and

[4] Pyttel B, Schwerdt D, Berger C. Very high cycle fatigue—Is there a fatigue limit? International Journal of Fatigue.

[5] ASTM-E466-15, Standard Practice for Conducting Force Controlled Constant Amplitude Axial Fatigue Tests

of Metallic Materials. West Conshohocken, PA, USA; 2015

Tubular Specimens. West Conshohocken, PA, USA; 2015

1910;10(Part 11):625

[6] International Organization for Standardization ISO 1143: 2010 (E). Metallic Materials–Rotating Bar Bending Fatigue Testing. Geneva, Switzerland;

[7] ASTM-E2207-15, Standard Practice for Strain-Controlled Axial-Torsional Fatigue Testing with Thin-Walled

[8] Basquin OH. The exponential law of endurance tests. American Society for Testing and Materials Proceedings.

[9] Liu WC et al. High cycle fatigue behavior of as-extruded ZK60

magnesium alloy. Journal of Materials Science. 2009;44(11):2916-2924

[10] Liu W et al. Effect of shot peening on surface characteristics and fatigue

[3] ASTME1823-13, Standard

Fracture Testing. 2013

2011;33(1):49-58

2010

57

In addition, fatigue life of AZ31 can be improved by using nano-particulates of aluminum oxide and micron size nickel particles reinforcements as shown in Figure 14.
