scholarly journals Sensitivity of material failure to surface roughness: a study on titanium alloys Ti64 and Ti407

2020 ◽  
pp. 109438
Author(s):  
Scott Sneddon ◽  
Yang Xu ◽  
Mark Dixon ◽  
David Rugg ◽  
Peifeng Li ◽  
...  
2011 ◽  
Vol 264-265 ◽  
pp. 1154-1159
Author(s):  
Anayet Ullah Patwari ◽  
A.K.M. Nurul Amin ◽  
S. Alam

Titanium alloys are being widely used in the aerospace, biomedical and automotive industries because of their good strength-to-weight ratio and superior corrosion resistance. Surface roughness is one of the most important requirements in machining of Titanium alloys. This paper describes mathematically the effect of cutting parameters on Surface roughness in end milling of Ti6Al4V. The mathematical model for the surface roughness has been developed in terms of cutting speed, feed rate, and axial depth of cut using design of experiments and the response surface methodology (RSM). Central composite design was employed in developing the surface roughness models in relation to primary cutting parameters. The experimental results indicate that the proposed mathematical models suggested could adequately describe the performance indicators within the limits of the factors that are being investigated. The developed RSM is coupled as a fitness function with genetic algorithm to predict the optimum cutting conditions leading to the least surface roughness value. MATLAB 7.0 toolbox for GA is used to develop GA program. The predicted results are in good agreement with the experimental one and hence the model can be efficiently used to achieve the minimum surface roughness value.


2011 ◽  
Vol 175 ◽  
pp. 289-293 ◽  
Author(s):  
Hao Liu ◽  
Chong Hu Wu ◽  
Rong De Chen

Side milling Ti6Al4V titanium alloys with fine grain carbide cutters is carried out. The influences of milling parameters on surface roughness are investigated and also discussed with average cutting thickness, material removal rate and vibration. The results reveal that the surface roughness increases with the increase of average cutting thickness and is primarily governed by the radial cutting depth.


2020 ◽  
Vol 7 ◽  
pp. 34 ◽  
Author(s):  
Samuel Ranti Oke ◽  
Gabriel Seun Ogunwande ◽  
Moshood Onifade ◽  
Emmanuel Aikulola ◽  
Esther Dolapo Adewale ◽  
...  

Machining is one of the major contributors to the high cost of titanium-based components. This is as a result of severe tool wear and high volume of waste generated from the workpiece. Research efforts seeking to reduce the cost of titanium alloys have explored the possibility of either eliminating machining as a processing step or optimising parameters for machining titanium alloys. Since the former is still at the infant stage, this article provides a review on the common machining techniques that were used for processing titanium-based components. These techniques are classified into two major categories based on the type of contact between the titanium workpiece and the tool. The two categories were dubbed conventional and non-conventional machining techniques. Most of the parameters that are associated with these techniques and their corresponding machinability indicators were presented. The common machinability indicators that are covered in this review include surface roughness, cutting forces, tool wear rate, chip formation and material removal rate. However, surface roughness, tool wear rate and metal removal rate were emphasised. The critical or optimum combination of parameters for achieving improved machinability was also highlighted. Some recommendations on future research directions are made.


2020 ◽  
Vol 836 ◽  
pp. 63-70
Author(s):  
Vyacheslav V. Maksarov ◽  
Alexander E. Efimov ◽  
Taras S. Golikov

This paper proposed a new method for processing titanium alloys based on preliminary plastic impact. The reasons for the deterioration of the surface roughness of titanium alloys during machining are considered. This problem lies in the formation of outgrowths on tool cutting wedge, which leads to the cutting process taking place as in the titanium-titanium pair. The adsorption phenomenon leads to the fact that the outgrowth is saturated with gases from the environment, and a thick oxide film is formed. As a result, high temperatures arise during machining from 1100 to 1200°C, increasing the cutting forces P and friction Q, which introduce the technological system into an unstable self-oscillating process. The problem posed eliminated by the method of preliminary plastic deformation, which forms a local inhomogeneous structure. At the stage of processing the titanium billet, the cutting edge enters the region with a heterogeneous structure, destroying the chips and growth with an oxide film. Since most of the temperature, about 80% takes away with the chips, the amplitude of the self-oscillating process decreases, which reduces the surface roughness of the processed titanium alloys.


2009 ◽  
Vol 83-86 ◽  
pp. 1059-1068 ◽  
Author(s):  
Armansyah Ginting ◽  
Mohammed Nouari ◽  
Nadhir Lebaal

In this paper, the surface integrity is studied when machining the aeronautical titanium alloys. Surface roughness, lay, defects, microhardness and microstructure alterations are studied. The result of surface roughness judges that the CVD-coated carbide fails to produce better Ra value than the uncoated. Lay is characterized by cutting speed and feed speed directions. Feed mark, tearing surface, chip layer formation as built up layer (BUL), and deposited microchip are the defects. Microhardness is altered down to 350 microns beneath the machined surface. The first 50 microns is the soft sub-surface caused by thermal softening in ageing process. Microstructure alteration is observed in this sub-surface. Down to 200 microns is the hard sub-surface caused by the cyclic internal work hardening and then it is gradually decreasing to the bulk material hardness. It is concluded that dry machining titanium alloy is possible using uncoated carbide with cutting condition limited to finish or semi-finish for minimizing surface integrity alteration.


Author(s):  
Neelesh Ku. Sahu ◽  
A. B. Andhare

Surface roughness is an important surface integrity parameter for difficult to cut alloys such as Titanium alloys (Ti-6Al-4V). In the present work, initially a mathematical model is developed for predicting surface roughness for turning operation using Response Surface Methodology (RSM). Later, a recently developed advanced optimization algorithm named as Teaching Learning Based Optimization (TLBO) is used for further parameter optimization of the equation developed using RSM. The design of experiments was performed using central composite design (CCD). Analysis of variance (ANOVA) demonstrated the significant and non-significant parameters as well as validity of predicted model. RSM describes the effect of main and mixed (interaction) variables on the surface roughness of titanium alloys. RSM analysis over experimental results showed that surface roughness decreased as cutting speed increased whereas it increased with increase in feed rate. Depth of cut had no effect on surface roughness. By comparing the predicted and measured values of surface roughness the maximum error was found to be 7.447 %. It indicates that the developed model can be effectively used to predict the surface roughness. Further optimization of the roughness equation was carried out by TLBO method. It gave minimum surface roughness as 0.3120 μm at the cutting speed of 1704 RPM (171.217 m/min), feed rate of 55.6 mm/min (.033 mm/rev) and depth of cut of 0.7 mm. These results were confirmed by confirmation experiment and were better than that of RSM.


2016 ◽  
Vol 36 (1) ◽  
pp. 12-17 ◽  
Author(s):  
Iwona Wstawska ◽  
Krzysztof Ślimak

Abstract Titanium alloys are one of the materials extensively used in the aerospace industry due to its excellent properties of high specific strength and corrosion resistance. On the other hand, they also present problems wherein titanium alloys are extremely difficult materials to machine. In addition, the cost associated with titanium machining is also high due to lower cutting velocities and shorter tool life. The main objective of this work is a comparison of different cooling techniques during cryogenic machining of titanium alloys. The analysis revealed that applied cooling technique has a significant influence on cutting force and surface roughness (Ra parameter) values. Furthermore, in all cases observed a positive influence of cryogenic machining on selected aspects after turning and milling of titanium alloys. This work can be also the starting point to the further research, related to the analysis of cutting forces and surface roughness during cryogenic machining of titanium alloys.


2017 ◽  
Vol 1142 ◽  
pp. 250-253
Author(s):  
Ze WU ◽  
You Qiang Xing ◽  
Peng Huang

Textured self-lubricating tools were fabricated by fiber laser machining. Dry milling of titanium alloys was carried out with these textured tools and conventional one for comparison. The cutting forces, cutting temperature, surface roughness of processed workpiece and tool flank wear were measured. Results show that the textured tools can reduce the cutting forces, cutting temperature and surface roughness of workpiece, as a result, present superior wear-resistance compared to the untextured tool.


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