hosseini1 -
	Interesting refs -
		[2] Shabnam Hosseini, M.B.Limooei,?Investigation of fatigue behavior and notch sensitivity
of Ti-6Al-4V?, Applied Mechanics and Materials, 80-81, 7, 2001.
		[4] Shabnam Hosseini, H. Arabi, M. Tamizifar and A. Zeyaei, ?Effect of tensile strength on
behavior and notch sensitivity of Ti-6Al-4V?, Iranian journal of materials science and
engineering, Vol.3, Winter & Spring 2006, PP.12-16.
		[15] R.J.Morrissey, D.L.McDowell, T.Nicholas, ?Frequency and stress ratio effects in high
cycle fatigue of Ti-6Al-4V?, International of Fatigue, 21,1999, 679-685.
		[18] D.B.Lanning, G.K.Haritos, T.Nicholas, ?Influence of Stress State in HCF of Notched Ti-
6Al-4V Specimens?, Int.J.of Fatige, Vol.21, 1999, S87-S95.
		[21] G.K. Haritos, T. Nicholas, D.B. Lanning, ?Notch Size Effect in HCF Behaviour of Ti-6Al-
4V?, Int. J. of Fatigue, 21, 1999, PP. 643-652.
		[22] Shabnam Hosseini, ?Effect of Mechanical Parameter on Fatigue Behavior of Ti-6Al-4V?,
Master of Science Theseis, Fall 2002.

	Biocompatible ti's -
		These first generation orthopedic alloys included Ti-6Al-7Nb and Ti-5Al-2.5Fe. (p. 76)
		second generation titanium orthopedic alloys including Ti-12Mo-6Zr-2Fe (TMFZ), Ti-15MO-5Zr-3Al, Ti-15Mo-3Nb-3O, Ti-15Zr-4Nb-2Ta-0.2Pd and Ti-15Sn-4Nb-2Ta-0.2Pd alloys, as well as the completely biocompatible Ti-13Nb-13Zr alloy [6] (p. 77)
	
	Titanium alloys may be classified as either à, near-à, à+beta, metastable beta or stable beta depending upon their room temperature microstructure. IN this regard alloying elements for titanium fall into three categories: à-stabilizers, such as Al, O, N, C, beta-stabilizer such as Mo, V, Nb, Ta, Fe, W, Cr, Si, Ni, Co, Mn, H and neutral, such as Zr. ? and near-à titanium alloys exhibit superior corrosion resistance with their utility as biomedical materials being principally limited by their low ambient temperature strength. In contrast, à+beta alloys exhibit higher strength due to the presence of both à and beta phases. Their properties depend upon composition, the relative proportions of the à/beta phases, and the alloy's prior thermal treatment and thermo-mechanical processing conditions. beta alloys(metastable or stable) are titanium alloys with high strength, good formability and high hardenability. beta alloys also offer the unique possibility of combined low elastic modulus and superior corrosion resistance[8]. (p. 78)
	
	Ti-6Al-4V is generally considered as a standard material when evaluating the fatigue resistance of new orthopedic titanium alloys. The mechanical response of Ti-6Al-4V alloy is, however, extremely sensitive to prior thermo-mechanical processing history, e.g., prior beta grain size, the ratio of primary à to transformed beta, the à grain size and the à/beta morphologies, all impacting performance, particularly high-cycle fatigue lifetime (HCF). (p. 83)
	
	The alpha phase tends to control the mechanical properties of this alloy when used at low temperature. In addition to alpha grain size, the fatigue life of Ti-6Al-4V components is influenced by the amount of age hardening, oxygen content, and grain morphology [17]. High cycle fatigue tests performed on Ti-6Al- 4V showed that by decreasing alpha grain size, fatigue properties of both smooth and notched (Kt=1.8) specimens, can be improved [18].

Get more info on freq effects.
Scan Neppiras[2]; upload if allowed.

(Static compressive stresses have no effect on fatigue.) --> true?

6/Dec/2017 23:23
	40k ti SN tests - analyze failure locations wrt node (highest stress)

4/Dec/2017 16:08
	In slotted bar horns, slots typically crack at the slot-radius transition. Can slot stress be reduced 
		- With a keyhole slot?
		- By applying a compressive stress to the slot hole (see Campbell1, p. 260+) before adding the slot?
			(Theoretically, how does slot stress Kt (CARD says 2.4) compare to hole stress (3.0)?)
			What happens to the compressive stress after the slot is machined?
			
	Corrosive environment
		Milk carton sealing - what liquid was equip sprayed with?

	Steel parts subjected to wear conditions are often carburized or nitrided to harden the surface for greater wear resistance. Since both of these processes also introduce residual compressive stresses on the surface, there is an improvement in fatigue life. The greatest improvement occurs where a high stress gradient occurs, as in bending or torsion, with less improvement in axial loading. (Campbell1, p. 261)