Microstructural characterization of friction-stir processed Ti-6Al-4V

The present work was undertaken to shed additional light on the globular-α microstructure produced during FSP of Ti-6Al-4V. To this end, the electron backscatter diffraction (EBSD) technique was employed to characterize the crystallographic aspects of such microstructur

Influence of deposition strategies on tensile and fatigue properties in a wire + arc additive manufactured Ti-6Al-4V

This paper investigates the influence of two different deposition strategies, oscillation and parallel pass, on the tensile and high cycle fatigue properties of a wire + arc additive manufactured Ti-6Al-4V alloy in the as-built condition. In the oscillation build, the plasma torch and the wire feeder continuously oscillated across the wall thickness direction. In contrast, four single layers were deposited consecutively in the same direction along the wall length in the parallel pass build. Test specimens were manufactured in horizontal and vertical orientation with respect to the deposited layers. Compared with the parallel pass build, the oscillation build had lower static strength due to its coarser transformation microstructure. However, the elongation values were similar. The presence of columnar primary β grains has resulted in anisotropic elongation values. The vertical samples with loading axis parallel to the primary β grains showed 40% higher elongation than the horizontal samples. The fatigue strength was comparable with its wrought counterpart and greater than typical material by casting. At 107 cycles, fatigue strength of 600 MPa was achieved for the oscillation build vertical samples and the parallel pass build in both orientations. Only the oscillation build horizontal samples had lower fatigue strength of 500 MPa. Fractography analysis showed that most of the samples (about 70%) had crack initiation from pores, about 20% samples had crack initiated from microstructural features and the rest did not failed (runouts at 107 cycles)

The role of microstructure and local crystallographic orientation near porosity defects on the high cycle fatigue life of an additive manufactured Ti-6Al-4V

Titanium alloys such as Ti-6Al-4V built by most of the additive manufacturing processes are known to contain process induced defects, non-conventional microstructure and strong crystallographic texture; all of which can affect the fatigue strength. In this study we evaluated the effect of crystallographic orientation of α and α lath width around gas pore defects on the high cycle fatigue life of Wire + Arc Additive Manufactured Ti-6Al-4V by means of Electron Back Scattered Diffraction. Here we show that variations in crystallographic orientation of α lath and its width in the vicinity of the crack initiating defect were the main reasons for the considerable scatter in fatigue life. Pyramidal slip systems with high Schmid factor active around the defects resulted in longer fatigue life compared to pyramidal slip with lower Schmid factor. In the absence of pyramidal slip, cracks initiated from active prismatic slip systems. When considering the influence of the microstructure, a higher number of smaller α laths around the defect resulted in longer fatigue life, and vice versa. Overall, the fatigue crack initiation stage was controlled collectively by the complex interaction of porosity characteristics, α lath width and its crystallographic orientation at the crack initiation locatio

Mental health benefits of therapeutic riding programs

This study investigated the psychological benefits of therapeutic riding programs. Participants (N=35) consisted of individuals in therapeutic riding and therapeutic skiing programs. Participants completed a questionnaire package assessing their self-esteem, symptoms of anxiety and depression and locus of control prior to treatment and again, approximately three months later, when the session of riding or the season of skiing had ended. Results indicated that both groups of participants showed significant improvements in self-esteem and locus of control as well as a decrease in symptoms of anxiety and depression after treatment. Twenty participants took part in post-treatment interviews, which looked more specifically at program benefits. Both groups revealed that the therapeutic program increased their self-esteem, made them feel better about themselves and provided social benefits. However, participants in the therapeutic riding program additionally experienced a connection to the therapeutic animal, a sense of community within the equestrian environment and a feeling of prestige and specialness that was associated with being able to ride a horse. Interactions with the therapeutic horse also increased motivation to engage in and remain in treatment. These results demonstrate that therapeutic riding programs can have a beneficial effect on mental health functioning and can provide additional, unique benefits not available in other therapeutic programs. The relationship that is developed with the horse and the intrinsic sense of community that is experienced appears to be particularly important treatment components of the program.Ph.D

The effect of animal presence on perceptions of psychotherapists and disclosure in therapy

This study examined the impact of animal presence on perceptions of therapists and willingness to self-disclose in therapy. Participants (N = 85) viewed a video clip of a psychotherapist alone or in the presence of a dog and then completed questionnaires assessing their perceptions of the therapist, willingness to disclose and attitude toward animals. Results indicated that participants rated the psychotherapists more favourable on several interpersonal characteristics and were more willing to disclose when the animal was present. Refuting past critiques, the presence of an animal had a beneficial impact on perceptions and willingness to disclose regardless of an individual's overall attitude toward animals. These results demonstrate that the presence of a dog, and perhaps other animals, can enhance the way psychotherapists are perceived and may also have a role in strengthening the therapeutic alliance.M.A