Vitus Mwinteribo Tabie, Chong Li, Wang Saifu, Jianwei Li and Xiaojing Xu
This paper aims to present a broad review of near-a titanium alloys for high-temperature applications.
Abstract
Purpose
This paper aims to present a broad review of near-a titanium alloys for high-temperature applications.
Design/methodology/approach
Following a brief introduction of titanium (Ti) alloys, this paper considers the near-α group of Ti alloys, which are the most popular high-temperature Ti alloys developed for a high-temperature application, particularly in compressor disc and blades in aero-engines. The paper is relied on literature within the past decade to discuss phase stability and microstructural effect of alloying elements, plastic deformation and reinforcements used in the development of these alloys.
Findings
The near-a Ti alloys show high potential for high-temperature applications, and many researchers have explored the incorporation of TiC, TiB SiC, Y2O3, La2O3 and Al2O3 reinforcements for improved mechanical properties. Rolling, extrusion, forging and some severe plastic deformation (SPD) techniques, as well as heat treatment methods, have also been explored extensively. There is, however, a paucity of information on SiC, Y2O3 and carbon nanotube reinforcements and their combinations for improved mechanical properties. Information on some SPD techniques such as cyclic extrusion compression, multiaxial compression/forging and repeated corrugation and straightening for this class of alloys is also limited.
Originality/value
This paper provides a topical, technical insight into developments in near-a Ti alloys using literature from within the past decade. It also outlines the future developments of this class of Ti alloys.
Details
Keywords
Sabeen Hussain Bhatti, Saifullah Khalid Kiyani, Scott B. Dust and Ramsha Zakariya
Although the use of project teams is on the rise, there is a limited understanding of how project managers can ensure project team success. Research to date is relatively broad…
Abstract
Purpose
Although the use of project teams is on the rise, there is a limited understanding of how project managers can ensure project team success. Research to date is relatively broad and does not pinpoint how and why leadership influences success in a project team context. Along these lines, we draw from social learning theory to illustrate that ethical leadership influences project success through leader trust and knowledge sharing.
Design/methodology/approach
We collected data from 175 project team members from the information technology and software industry to evaluate our hypotheses. The results were analyzed using structural equation modeling.
Findings
Our findings support our hypotheses, illustrating that ethical leadership is related to leader trust and knowledge sharing, and that leader trust and knowledge sharing mediate the relationship between ethical leadership and project success.
Research limitations/implications
Our work illustrates that the behaviors inherent in ethical leadership may be particularly well-suited for these project team challenges. Ethical leaders help team members understand that project success is possible when team members are transparent with one another, discussing their goals and challenges, and then working together to ensure their actions are coordinated in a way that increases the success of the overall project.
Practical implications
For those in industries or organizations where project teams are commonly used, our study may help to attract, select, and retain project managers that exhibit ethical leadership tendencies. Project managers are likely to be attracted to settings that align with their leadership style. Thus, organizations could focus on developing a culture that focuses on process over results.
Originality/value
We sought to align with the contingency approach to leadership, which suggests that the ideal leadership style depends on the followers, and the context in which the leader and followers interact. Specifically, we investigate ethical leadership as an ideal approach for project managers influencing members of their project teams. Our study demonstrates how ethical leadership is an ideal, context-specific approach that project managers can apply to increase the chances of project success.
Details
Keywords
Bo Chen, Tao Wang, Xin Xi, Caiwang Tan and Xiaoguo Song
Ti-Al composite plates have been used in aerospace and other important fields for specific purposes in recent years. However, relatively few studies have concentrated on Ti-Al…
Abstract
Purpose
Ti-Al composite plates have been used in aerospace and other important fields for specific purposes in recent years. However, relatively few studies have concentrated on Ti-Al additive manufacturing because during additive manufacturing process the local fusion and mixing of Ti/Al are inevitable. These areas where Ti and Al are mixed locally, especially interface, could easily generate high residual stresses and cracks. This study aims to manufacture Ti-Al functionally graded material and investigate the interaction of interface.
Design/methodology/approach
In this study, Ti6Al4V/AlSi10Mg functionally graded materials were fabricated by laser based directed energy deposition (L-DED) and a strategy using V interlayer to relieve interfacial stress was investigated.
Findings
The area between the two materials was divided into transition zone (TZ) and remelting zone (RZ). The phase distribution, microstructure and micro-Vickers hardness of the TZ and RZ were investigated. Typical intermetallic compounds (IMCs) such as TiAl3, Ti3Al and Ti5Si3 were found in both composites. The addition of V interlayer promoted the homogenization of IMCs near interface and led to the formation of new phases like V5Si3 and Al3V.
Originality/value
The solidification process near the interface of Ti-Al functionally graded material and the possible generation of different phases were described. The result of this paper proved the feasibility of manufacturing Ti-Al functionally graded material by L-DED.