Surface modification of titanium and titanium alloys: Technologies, developments, and future interests

Welding and Joining of NiTi Shape Memory Alloys: A Review

Effects of scan line spacing on pore characteristics and mechanical properties of porous Ti6Al4V implants fabricated by selective laser melting

Effect of heat treatment on the phase transformation and mechanical properties of Ti6Al4V fabricated by selective laser melting

A three-dimensional model was developed for studying thermal behavior during selective laser melting (SLM) of commercially pure titanium (CP Ti) powder. The effects of scan speed and laser power on SLM thermal behavior were investigated. The results showed that the average temperature of the powder bed gradually increased during the SLM process, caused by a heat accumulation effect. The maximum molten pool temperature (2248 °C) and liquid lifetime (1.47 ms) were obtained for a successful SLM process for a laser power of 150 W and a laser scan speed of 100 mm/s. The temperature gradient in the molten pool increased slightly (from 1.03 × 10 4 to 1.07 × 10 4  °C/mm in the direction perpendicular to the scanning path; from 1.21 × 10 4 to 1.28 × 10 4  °C/mm in the thickness direction) when the scan speed was increased from 50 to 200 mm/s, but increased significantly (from 1.29 × 10 4 to 8.24 × 10 4  °C/mm in the direction perpendicular to the scanning path; from 1.53 × 10 4 to 9.84 × 10 4  °C/mm in the thickness direction) when the laser power was increased from 100 to 200 W. The width and depth of the molten pool decreased (width from 137.1 to 93.8 μm, depth from 64.2 to 38.5 μm) when the scan speed was increased from 50 to 200 mm/s, but increased (width from 71.2 to 141.4 μm, depth from 32.7 to 67.3 μm) when the laser power was increased from 100 to 200 W. Experimental SLM of CP Ti powder was carried out under different laser processing conditions and the microstructure of SLM-produced parts was investigated to demonstrate the reliability of the physical model and simulation results.

Thermal behavior during selective laser melting of commercially pure titanium powder: Numerical simulation and experimental study

A study of the microstructure and hardness of two titanium alloys: Commercially pure and Ti–6Al–4V

A noticeable reduction in the cost of structural components made from titanium, both commercially pure and the alloy counterpart is possible with the concept of built-up welded fabrication. Rolled sheets of the titanium material can be welded together to fabricate a built-up structural component without having to machine the part from a large billet. In this paper, the results of a recent feasibility study on the manufacturing of welded built-up I-beams for large structural applications are presented and discussed. The fillet welds were produced using the pulsed Gas Metal Arc Welding (GMAW-P) process. Commercially pure titanium (Grade 2) and a titanium alloy (Ti-6Al-4 V) were the two materials chosen for the study. The specific details of the welding process are highlighted along with a discussion of the successful implementation of the concept of built-up welded beams for the manufacture of large structural elements and components of titanium.

On the Use of Gas Metal Arc Welding for Manufacturing Beams of Commercially Pure Titanium and a Titanium Alloy

During the last two decades, titanium has gradually grown in stature, strength and significance to take on the recognition of being a modern and high performance metal that is noticeably stronger and concurrently lighter than the most widely chosen and used steels in a spectrum of industrial applications. Technological innovations have necessitated reduction of part weight, cost and lead time, including concurrent enhancement of performance of structural parts and components made using titanium and its alloys. This has provided the impetus to develop economically viable structural design methodologies and specifications, while at the same time bringing forth innovative and economically affordable manufacturing and fabricating techniques with the primary purpose of both producing and promoting the use of cost-effective titanium structures. The experimental results of a recent study on built-up welded beams are presented in this paper with the primary objective of enabling design, facilitating fabrication, and implementation of large structural members for potential applications in the structural and defense-industry.

Understanding the Mechanical Response of Built-Up Welded Beams Made from Commercially Pure Titanium and a Titanium Alloy

In this article, the results of a recent study aimed at evaluating, understanding, and rationalizing the extrinsic influence of fatigue loading on the response characteristics of built-up welded beams made from commercially pure titanium (Grade 2) are presented and discussed. The beams were made from welding plates and sheets of titanium using the pulsed gas metal arc welding technique to form a structural beam having an I-shaped cross section. The welds made for the test beams of the chosen metal were fillet welds using a matching titanium filler metal wire. The maximum and minimum load values at which the built-up beams were cyclically deformed were chosen to be within the range of 22-45% of the maximum predicted flexural static load. The beams were deformed in fatigue at a stress ratio of 0.1 and constant frequency of 5 Hz. The influence of the ratio of maximum load with respect to the ultimate failure load on fatigue performance, quantified in terms of fatigue life, was examined. The percentage of maximum load to ultimate load that resulted in run-out of one million cycles was established. The overall fracture behavior of the failed beam sample was characterized by scanning electron microscopy observations to establish the conjoint influence of load severity, intrinsic microstructural effects, and intrinsic fracture surface features in governing failure by fracture.

Narendra Poondla

Papers

A study of the microstructure and hardness of two titanium alloys: Commercially pure and Ti–6Al–4V

On the Use of Gas Metal Arc Welding for Manufacturing Beams of Commercially Pure Titanium and a Titanium Alloy

Understanding the Mechanical Response of Built-Up Welded Beams Made from Commercially Pure Titanium and a Titanium Alloy

The Fatigue Behavior of Built-Up Welded Beams of Commercially Pure Titanium

Investigating and Understanding the Fatigue Response and Failure of Built-Up Welded Beams of a Titanium Alloy