Fatigue Property and Cytocompatibility of a Biomedical Co–Cr–Mo Alloy Subjected to a High Pressure Torsion and a Subsequent Short Time Annealing

Abstract

In the present study, we evaluated the effects of high pressure torsion (HPT) and subsequent short time annealing processing on fatigue properties and cytocompatibility of the biomedical CoCrMo alloy (CCM). Before processing, CCM was solution treated (CCM ST) to achieve a microstructure composed of coarse single £-phase equiaxed grains with no internal strain. Through HPT processing, an inhomogeneous microstructure containing both micro-and nano-scaled grains is obtained in CCM specimens, which were named as CCM HPT , accompanied by high internal strain and extensive ¾ martensite. Following a subsequent short time annealing, a uniform single £-phase ultrafine-grained microstructure with small local strain fields dispersed forms in CCM specimens, which were named as CCM HPTA. This microstructure change improves fatigue strength in CCM HPT , and further in CCM HPTA , because of the enhanced crack initiation and/or propagation resistance. For cytocompatibility evaluation, the cells cultured on CCM ST show an immobilization tendency, while those cultured on CCM HPT exhibit a locomotion tendency. The cells cultured on CCM HPTA have an intermediate pattern. Compared with CCM ST , much larger numbers of cells are proliferated in both CCM HPT and CCM HPTA. All these results demonstrate that the CCM HPTA offers an improved fatigue property and a good cytocompatibility. Therefore, it is promising for use in biomedical applications.

Metals and Medicine

“…113) The fatigue property and cytocompatibility of a biomedical CoCrMo alloy subjected to HPT processing, and a short subsequent time of annealing, has also been studied. 114)…”

Evaluation of cytocompatibility and osteoconductivity of Zr-14Nb-5Ta-1Mo alloy with MC3T3-E1 cells

“…A mouse calvaria-derived preosteoblast cell line, MC3T3-E1, was purchased from RIKEN BioResource Center (Tsukuba, Japan) and used directly. As described in previous reports [28][29][30] , cells were cultured at 37°C in a humidified atmosphere of 5% CO2 in air and maintained in a growth medium composed of the minimum essential medium Eagle with alpha modification (α-MEM, Sigma-Aldrich, St. Louis, MO, USA) supplemented with 10% fetal bovine serum and 100 U L-glutamine-penicillinstreptomycin solution (G1146, Sigma-Aldrich).…”

“…The cellular proliferation of each specimen was evaluated by the number of attached cells on both specimens using the Cell Counting Kit-8 (CCK-8, Dojindo Laboratories, Kumamoto, Japan) for five consecutive days. The absorbance of each specimen was measured at 450 nm using a microplate reader (ChroMate 4300, Awareness Technology, Palm City, FL, USA) according to manufacturer's instructions [28][29][30] . In addition, a tissueculture polystyrene dish (TCPS) was employed as a control.…”

Effect of Room Temperature Fine Particle Peening Pretreatment on Grain Refinement of Fe–Cr Alloys by AIH-FPP

“…Grain refinement is an effective procedure to improve the fatigue strength of metallic materials. Various technologies, such as cold rolling, 1,2) warm rolling, 3) equal channel angular pressing, 4) and high-pressure torsion 5,6) are applied to obtain fine grains, and their effects on the mechanical properties of metals have been investigated. However, grain refinement generally leads to a reduction of ductility, and compatibility between ductility and fatigue strength is necessary.…”