The fatigue strength, effects of a notch on the fatigue strength, and fatigue crack growth rate of Ti-15Zr-4Nb-4Ta alloy were compared with those of other implantable metals. Zr, Nb, and Ta are important alloying elements for Ti alloys for attaining superior long-term corrosion resistance and biocompatibility. The highly biocompatible Ti-15Zr-4Nb-4Ta alloy exhibited an excellent balance between...

A method is presented to use a dimensionless form of the well-known Niyama criterion to directly predict the amount of shrinkage porosity that forms during solidification of metal alloy castings. The main advancement offered by this method is that it avoids the need to know the threshold Niyama value below which shrinkage porosity forms; such threshold values are generally unknown and alloy dep...

The purpose of this study was to evaluate the effect of acidic primers on bonding magnetic steel alloys. Three alloys (XM27, 447J1, and AUM20) were primed with one of the following materials: Acryl Bond, Estenia Opaque Primer, Eye Sight Opaque Primer, M. L. Primer, or Super-Bond liquid. The specimens were bonded with a tri-n-butylborane initiated resin, and bond strength was determined both bef...

A model is developed to calculate the composition of reoxidation inclusions that form during pouring of steel castings. The software package Thermo-Calc is used to obtain the inclusion phase fractions and compositions as a function of the temperature and oxygen content of the steel. Oxygen is assumed to be continually absorbed by the steel until the liquidus temperature is reached. Both lever r...

OBJECTIVE The objective of this study was to test the hypothesis that there is no difference between stainless steel and low-nickel stainless steel wires as regards mechanical behavior. Force, resilience, and elastic modulus produced by Quad-helix appliances made of 0.032-inch and 0.036-inch wires were evaluated. METHODS Sixty Quad-helix appliances were made, thirty for each type of alloy, be...

the openings of copper converter in sarcheshmeh copper complex in iranis made of a heat resisting austenitic steel (fe-25cr-12ni) and many failures have been reported. understanding the failure mechanism of the alloy helps to develop better alloys for similar complex environments. samples of as-cast alloy and those taken from failed ones were examined. optical microscopy (om), x-ray diffraction...

Abstract: During the last decade, the demand for natural gas has steadily increased for the prevention of environmental pollution. For this reason, many liquefied natural gas (LNG) carriers have been manufactured. Since one of the most important issues in the design of LNG carriers is to guarantee structural safety, the use of low-temperature materials is increasing. Among commonly employed low...

Surface treatments of engineering materials are important for serviceable engineering components. One of the thermo-chemical surface treatments of steel based materials is the boriding process. In this study, low alloy steel substrates were borided by pack boriding process at 900 C. Experimental indentation tests were conducted on Dynamic Ultra-micro Hardness test machine, under applied peak lo...

A stent in artery is subjected to significant mechanical loads due to the repetitive cyclical pressure loads and displacement of the artery wall. The arteries expands and contracts slightly as the pressure changes with the heart beat for long-term in-vivo service. The structure of the stent has to withstand these loads while scaffolding the narrow artery. Many different stent designs and materi...

A clinical study was undertaken to compare the surface microbial contamination associated with pens constructed of either a copper alloy or stainless steel used by nurses on intensive care units. A significantly lower level of microbial contamination was found on the copper alloy pens.