http://sistemas.eel.usp.br/docentes/arquivos/2166002/1234Nb/Geetha-review2009.pdf

Ti based biomaterials, the ultimate choice for orthopaedic implants – A review

Young's modulus as well as tensile strength, ductility, fatigue life, fretting fatigue life, wear properties, functionalities, etc., should be adjusted to levels that are suitable for structural biomaterials used in implants that replace hard tissue. These factors may be collectively referred to as mechanical biocompatibilities. In this paper, the following are described with regard to biomedical applications of titanium alloys: the Young's modulus, wear properties, notch fatigue strength, fatigue behaviour on relation to ageing treatment, improvement of fatigue strength, fatigue crack propagation resistance and ductility by the deformation-induced martensitic transformation of the unstable beta phase, and multifunctional deformation behaviours of titanium alloys.

Mechanical biocompatibilities of titanium alloys for biomedical applications.

Overview no. 35 Dynamic recrystallization: Mechanical and microstructural considerations

The evolution of strength and crystalline phases for alkali-activated ground blast furnace slag and fly ash-based geopolymers

Powder metallurgy (PM) of titanium is a potentially cost-effective alternative to conventional wrought titanium. This article examines both traditional and emerging technologies, including the prod...

https://www.tandfonline.com/doi/pdf/10.1080/09506608.2017.1366003

Powder metallurgy of titanium – past, present, and future

Historical progress of Thermo-Mechanical Processing (TMP) in steels during a last half century is briefly reviewed in the first part of this paper. On-line accelerated cooling process in a wide plate mill was developed by a Japanese steel mill in the end of 1970's, and its equipment was installed into major steel plate mills in Japan and Europe in 1980's. The combination of controlled rolling and accelerated cooling called as TMCP provided a powerful means for microstructural control of hot rolled steel plates. Subsequently, direct quenching (DQ)-tempering process was industrialized, where direct quenching after finish-rolling was performed at the highest cooling rate available in the accelerated cooling equipment. Since then, various new steel plates have been developed by intensive use of TMCP and direct quenching process particularly in Japan. In the latter part of this paper, newly developed steel plates by use of TMCP or DQ process during last two decades were summarized based on classification of line pipe steel, weldable HSLA steel plates used for shipbuilding, offshore construction, building, bridge or penstock, and austenitic stainless steel plate. Various strengthening mechanisms such as grain refinement, precipitation hardening or strengthening due to transformed microstructures have been utilized in development of numerous TMCP and DQ steel plates.

Development of Steel Plates by Intensive Use of TMCP and Direct Quenching Processes

The effect of Nb content in HSLA steels on hot ductility was investigated under various thermal cycles. The increase of Nb content was found to deteriorate hot ductility in all the thermal cycles investigated. The change in hot ductility with temperature gave rise to only one trough in the temperature region from 700 to 900°C, which covered the lower temperature region of the austenite (I), and the γ-α region (II). The strain concentration in the ferrite primarily reduced hot ductility in the region II, and the increase of Nb content reduced hot ductility remarkably in region I, where grain boundary precipitates such as Nb(CN) primarily controlled hot ductility. The latter fact was confirmed through the studies of fractography and reversibility of hot ductility behavior. The improvement of hot ductility in the Nb-bearing steels was shown to be attained by adoption of the thermal cycle corresponding to hot charging process of the ingot or the slab, and also by the decrease of N content or the addition of the small amount of Ti. Relation between hot ductility and hot deformation mechanism, such as dynamic recrystallization or grain boundary sliding, is discussed.

/pdf/hot-ductility-in-nb-bearing-high-strength-low-alloy-steels-2zoji0exle.pdf

Hot ductility in Nb-bearing high-strength low-alloy steels.

A blended elemental titanium powder metallurgy process has been developed to offer low cost commercial products. The process employs hydride-dehydride (HDH) powders as well as Hunter sponge fines (SP) as raw materials. Mechanical properties of HDH products are comparable with those of SP products. A β-rich α + β alloy SP-700 (Ti-4.5A1-3V-2Fe-2Mo) has been applied to the process and its products show superior properties over Ti-6Al-4V: high sinterability, fine microstructure, excellent mechanical properties and good cold workability. Additions of iron and molybdenum to the alloy contribute to the enhancement of sintering and microstructure refinement, respectively. Sintered SP-700 products have been applied to various commercial parts.

Microstructure and properties of titanium alloy produced in the newly developed blended elemental powder metallurgy process

The effect of hot rolling condition and chemistry of steels on the onset temperature of γ-α transformation after hot rolling was investigated using a thermal analyzer developed for the measurement of Ar3 temperature after hot rolling. The changes of Ar3 temperature and austenitic microstructure in connection with reheating temperature, rolling temperature and reduction rate were investigated in a Si-Mn and a Nb-bearing steels. The results were analyzed based on the changes of the effective interfacial area per unit volume (Sv) that included both of the recrystallized and unrecrystallized grain boundaries and deformation band as nucleation sites for ferrite. Although the Sv value increased with the refinement of recrystallized γ grain or the increase of rolling reduction below recrystallization temperature of austenite, the latter resulted in a much greater change of Ar3 temperature in the Nb steel. This was considered to be due to a reduced amount of dissolved Nb atoms around the grain boundary or deformation band through the strain induced precipitation of Nb(CN).The effect of chemistry and plate thickness on the Ar3 temperature after controlled rolling was studied in a large number of steels with different chemistry, and the relation between the Ar3 and chemistry was quantitatively established based on the multiple regression analysis.

The Effect of Hot Rolling Condition and Chemical Composition on the Onset Temperature of γ-α Transformation after Hot Rolling

Various properties of pure titanium and titanium alloys with ultra- high purity prepared by melting raw titanium made by improved iodide process have been examined. Effects of oxygen, nitrogen and carbon addition to pure titanium and SP-700 alloy on tensile properties were investigated, and strengthening effect and ductility variation due to these elements were evaluated. The strength of pure titanium and SP-700 alloy markedly decreased with the increase of purity, the yield strength of pure titanium containing oxygen of 40 ppm being reduced to 100 MPa. The recrystallization temperature of cold rolled ultra-high purity titanium was extremely low, 553 K, a small amount of oxygen and iron doping markedly increased this temperature.

Chiaki Ouchi

Papers

Development of Steel Plates by Intensive Use of TMCP and Direct Quenching Processes

Hot ductility in Nb-bearing high-strength low-alloy steels.

Microstructure and properties of titanium alloy produced in the newly developed blended elemental powder metallurgy process

The Effect of Hot Rolling Condition and Chemical Composition on the Onset Temperature of γ-α Transformation after Hot Rolling

Effects of ultra-high purification and addition of interstitial elements on properties of pure titanium and titanium alloy