Study on Stability and Elastic Properties of β-TiX (X=Nb, Ta) Alloys From First-Principles Calculations

In this article, the phase stability, elastic properties, and electronic structure of the β-TiX (X = Nb, Ta) alloy body-centered cubic (bcc) structure were systematically studied with the aid of first-principles calculations. The results show that the phase stability and elastic properties of the β-TiX alloys are closely related to the contents of alloying element X. For β-TiX alloys, the contents of Nb and Ta that satisfy their mechanical stability are 10% and 13%, respectively; at room temperature, both β-TiNb and β-TiTa alloys can reach a thermodynamically stable state when the content of Nb or Ta is 25%. In terms of elastic properties, the content of alloying element X is positively correlated with the elastic constant, Young’s modulus, and shear modulus of the β-TiX alloys. The elastic modulus reaches its minimum when the X content is 25%, and the smallest direction of Young’s modulus appears in the <111> direction. The calculation results of the electronic structure show that the bonding strength between the Ti atom and X atom increases with the content of alloying element X, which leads to improvement of phase stability and elastic modulus

Microstructural and Mechanical Properties Characterization of Graphene Oxide-Reinforced Ti-Matrix Composites

The 0.1–0.7 wt.% graphene oxide (GO)-reinforced Ti-matrix composites (TMCs) were prepared by the hot-pressed sintering method. The effects of GO content on the mechanical properties of TMCs were investigated. The microstructure of TMCs was analyzed. The results show that the microstructure of Ti and TMCs is equiaxed α. The average grain size of TMCs decreases with GO increasing. GO can react with Ti to form TiC at high temperatures. Meanwhile, GO is also presented in the matrix. The hardness of TMCs is higher than that of pure Ti. The maximum hardness is 320 HV, which is 43% higher than that of pure Ti. The yield strength of Ti-0.5 wt.% GO sintered at 1373 K is 1324 MPa, 77% more than pure Ti. The strengthening mechanism of TMCs is the fine-grained strengthening and the reinforcement that bear the stress from the matrix. The friction coefficient of Ti-0.3 wt.% GO sintered at 1373 K comes up to 0.50, which is reduced by 0.2 compared with pure Ti

Microstructural and Mechanical Properties Characterization of Graphene Oxide-Reinforced Ti-Matrix Composites

The 0.1–0.7 wt.% graphene oxide (GO)-reinforced Ti-matrix composites (TMCs) were prepared by the hot-pressed sintering method. The effects of GO content on the mechanical properties of TMCs were investigated. The microstructure of TMCs was analyzed. The results show that the microstructure of Ti and TMCs is equiaxed α. The average grain size of TMCs decreases with GO increasing. GO can react with Ti to form TiC at high temperatures. Meanwhile, GO is also presented in the matrix. The hardness of TMCs is higher than that of pure Ti. The maximum hardness is 320 HV, which is 43% higher than that of pure Ti. The yield strength of Ti-0.5 wt.% GO sintered at 1373 K is 1324 MPa, 77% more than pure Ti. The strengthening mechanism of TMCs is the fine-grained strengthening and the reinforcement that bear the stress from the matrix. The friction coefficient of Ti-0.3 wt.% GO sintered at 1373 K comes up to 0.50, which is reduced by 0.2 compared with pure Ti.</jats:p

A Study on the Correlations of Anxiety and Depression With Self-Management Ability and Endogenous Creatinine Clearance Rate in Renal Transplant Recipients

Objective: To explore the effects of anxiety and depression on the self-management ability and endogenous creatinine clearance rate of renal transplant patients.Method: Eighty-eight renal transplant recipients who were followed up in the outpatient clinic of the Affiliated Hospital of Zunyi Medical University were selected using convenient sampling. The self-made general data sheet, Self-Rating Anxiety Scale, Self-Rating Depression Scale, and Self-Management Scale for Kidney Transplant Recipients were used. Correlation analysis was used to find factors related to endogenous creatinine clearance, while multiple linear regression was used to identify factors influencing endogenous creatinine clearance. Patients with or without anxiety and depression were divided into groups, and the indexes of the groups were compared using the independent samples t test, rank-sum test, or chi-squared test.Results: Anxiety was present in 12.5% of patients, depression in 25%, and a moderate level of self-management in 34.1%. Only 9.1% of renal transplant recipients had endogenous creatinine clearance within the normal range, and 34.1% had a body mass index not in the normal range (25% were overweight, and 9.1% were underweight). The endogenous creatinine clearance rate was negatively correlated with age and degree of depression, and positively correlated with body mass index, treatment management score, and psychosocial management score. The main influencing factors of endogenous creatinine clearance rate were age, sex, depression, body mass index, and treatment management score. The endogenous creatinine clearance rate and psychosocial management ability were significantly higher in patients without anxiety and depression than in patients with anxiety and depression (all P &amp;lt; 0.05).Conclusions: Anxiety and depression showed significant negative effects on the psychosocial self-management ability and endogenous creatinine clearance rate of renal transplant recipients and thus should be given more attention.</jats:p