A Study of the Tensile Deformation and Fracture Behavior of Commercially Pure Titanium and Titanium Alloy: Influence of Orientation and Microstructure

In this paper, the tensile deformation and fracture behavior of commercially pure titanium and the titanium alloy (Ti-6Al-4V) are presented and briefly discussed. Samples of both commercially pure titanium and the Ti-6Al-4V alloy were prepared from the as-provided plate stock along both the longitudinal and transverse orientations. The specimens were then deformed to failure in uniaxial tension. The intrinsic influence of material composition and test specimen orientation on microstructure, tensile properties, and resultant fracture behavior of the two materials is presented. The conjoint influence of intrinsic microstructural features, nature of loading, and specimen orientation on tensile properties of commercially pure titanium and the Ti-6Al-4V alloy is highlighted. The fracture behavior of the two materials is discussed taking into consideration the nature of loading, specimen orientation, and the role and contribution of intrinsic microstructural effects

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

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

A Study of Cyclic Fatigue, Damage Initiation, Damage Propagation, and Fracture of Welded Titanium Alloy Plate

In this paper, the influence of test specimen orientation and microstructure on cyclic stress-amplitude controlled fatigue response, damage initiation, damage propagation and fracture behavior of samples taken from a welded plate of titanium alloy is presented and discussed. Test specimens from the chosen alloy were prepared from an as-welded plate of the material with the stress axis both parallel (longitudinal) and perpendicular (transverse) to the deformed (rolling) direction of the plate. The test specimens were cyclically deformed at different values of maximum stress at a constant load ratio of 0.1, and the resultant cycles-to-failure was recorded. The fracture surfaces of the deformed and failed test specimens were examined in a scanning electron microscope to establish the macroscopic fracture mode, the intrinsic features on the fatigue fracture surface and the role of applied stress-microstructural feature interactions in establishing the microscopic mechanisms governing failure

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

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

Mechanisms Governing Fatigue, Damage, and Fracture of Commercially Pure Titanium for Viable Aerospace Applications

In this paper, the cyclic stress amplitude controlled high-cycle fatigue properties and final fracture behavior of commercially pure titanium (Grade 2) are presented and discussed. The material characterization was developed and put forth for selection and use in a spectrum of applications spanning the industries of aerospace, defense, chemical, marine, and commercial products. Test specimens were prepared from the as-received plate stock of the material with the stress axis both parallel (longitudinal) and perpendicular (transverse) to the rolling direction of the plate. The test specimens were cyclically deformed at a constant load ratio of 0.1, at different values of maximum stress, and the corresponding cycles-to-failure is presented. The cyclic fatigue fracture surfaces were examined in a scanning electron microscope to establish the macroscopic fracture mode, the intrinsic features on the fatigue fracture surface, and the role of applied stress-microstructural feature interactions in governing failure. The intrinsic features on the fracture surface as a function of maximum stress and resultant cyclic fatigue life are discussed

The Cyclic Fatigue and Final Fracture Behavior of a Titanium Alloy Taken from Weldments: Influence of Load Ratio and Orientation

In this paper, the cyclic stress ampliture controlled high cycle fatigue properties..