Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, in order to improve the biological, chemical, and mechanical properties, surface modification is often performed. This article reviews the various surface modification technologies pertaining to titanium and titanium alloys including mechanical treatment, thermal spraying, sol–gel, chemical and electrochemical treatment, and ion implantation from the perspective of biomedical engineering. Recent work has shown that the wear resistance, corrosion resistance, and biological properties of titanium and titanium alloys can be improved selectively using the appropriate surface treatment techniques while the desirable bulk attributes of the materials are retained. The proper surface treatment expands the use of titanium and titanium alloys in the biomedical fields. Some of the recent applications are also discussed in this paper.

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Surface modification of titanium, titanium alloys, and related materials for biomedical applications

Perspectives on Titanium Science and Technology

The activity of non-basal slip systems and dynamic recovery at room temperature in fine-grained AZ31B magnesium alloys

Metal Matrix Composites

http://li.mit.edu/Stuff/RHW/Upload/07-01_Lou_XY_Hardening_evolution_paper.pdf

Hardening evolution of AZ31B Mg sheet

Mechanical properties of alloys consisting of two ductile phases

The physical metallurgy of titanium alloys

An extensive literature review indicated that the law of mixture rule can at times account for stress-strain behavior of two-ductile phase alloys in terms of the stress-strain behavior of component phases. In the present investigation, various factors which can contribute to the stress-strain behavior of two-ductile phase alloys are considered, using Ti-Mn alloys as the model system. Particular attention is focused on the effect of elastic, elasto-plastic, and plastic interactions between the phases on the stress-strain behavior. It is shown that the law of mixture cannot adequately explain the stress-strain behavior. The following equation is proposed to describe the stress-strain behavior of two-ductile phase alloys: Pα-β = fαPαc+ fβPβc+ Iα-βp, where Pα-β is a given stress-strain property, fα and f/gb are respective volume fractions of α and β-phases, Pαc and Pβc are corrected properties of α and β-phases, and Iα-βp is the interaction term. It is found that for α- β Ti-Mn alloys, for 0.2 pct yield strength, Iα-βp is positive, negative, or zero depending on the microstructure; but Iα-βp is always positive for the ultimate tensile strength and strain hardening rates and its magnitude depended on the microstructure. The reasons for the nature or sign of the interaction parameter for a given property are discussed in detail.

A rationalization of stress-strain behavior of two-ductile phase alloys

Polycrystalline strengtheningDurcissement de polycristauxVerfestigung im polykristallinen material

By use of a NASTRAN18 Computer Program, the Finite Element Method (FEM) has been employed to calculate the effect of particle size, matrix, and volume fraction on the stress-strain relations of α-β titanium alloys. It was found that for a given volume fraction, the calculated stress-strain curve was higher for a finer particle size than for a coarse particle size within the range of the strains considered, and this behavior was seen for all the different volume fraction alloys considered. For a 50:50 vol pct α-β alloy, the stress-strain curve withβ, the stronger phase, as the matrix was higher than that with α, the softer phase, as the matrix. The calculated stress-strain curves for four different vol pct α alloys were compared with their corresponding experimental curves, and in general, good agreement was found. Whenever there were discrepancies, they were discussed by comparing the morphology of the mesh used in the calculations with the morphology of the actual materials.

Harold Margolin

Papers

Mechanical properties of alloys consisting of two ductile phases

The physical metallurgy of titanium alloys

A rationalization of stress-strain behavior of two-ductile phase alloys

Polycrystalline strengtheningDurcissement de polycristauxVerfestigung im polykristallinen material

Finite Element Method (FEM) Calculations of Stress-Strain Behavior of Alpha-Beta Ti-Mn Alloys: Part I. Stress-Strain Relations