Modeling of grain size in isothermal compression of Ti-6Al-4V alloy using fuzzy neural network

Abstract

Isothermal compression of Ti-6Al-4V alloy was conducted in the deformation temperature range of 1093-1303 K, the strain rates of 0.001, 0.01, 0.1, 1.0, and 10.0 s −1 , and the height reductions of 20%-60% with an interval of 10%. After compression, the effect of the processing parameters including deformation temperature, strain rate, and height reduction on the flow stress and the microstructure was investigated. The grain size of primary α phase was measured using an OLYMPUS PMG3 microscope with the quantitative metallography SISC IAS V8.0 image analysis software. A model of grain size in isothermal compression of Ti-6Al-4V alloy was developed using fuzzy neural network (FNN) with back-propagation (BP) learning algorithm. The maximum difference and the average difference between the predicted and the experimental grain sizes of primary α phase are 13.31% and 7.62% for the sampled data, and 16.48% and 6.97% for the non-sampled data, respectively. It can be concluded that the present model with high prediction precision can be used to predict the grain size in isothermal compression of Ti-6Al-4V alloy.

Flow Behaviour of Ti-6Al-4V Subjected to Multi Directional Isothermal Compression

“…Flow stresses are high at compression temperatures 1023 and 1073 when compared to that at compression temperature 1123 K. This is in good agreement with Luo and Li [19].…”

“…Thus, the dislocation density increases quickly with increasing of plastic strain. Then, the softening effect plays an important role in dislocation density evolution with the further increase of strain, which leads to the flow stress sharply decreasing to a steady value when the dynamic softening effect is sufficient to counteract the work-hardening effect [19]. Flow stress at 1123 K, in the first stage material is 106 MPa and after a compressive strain of 0.69 the flow stress is around 62 MPa.…”

Evaluation of Microstructure and Mechanical Properties of Titanium Alloy OT 4-1

“…Now a days, there is high demand for some special metals and alloys that can withstand high temperature, corrosion resistance and high strength to weight ratio. [1,9] OT 4-1 is a titanium alloy used for high-temperature application in the aerospace industry. These materials are extensively used in process industries, in paper and textile plants, in extractive metallurgy, in the oil industry, in medical sciences and in some engineering components such as steam and gas turbine blades, connecting rods, crankshafts etc.…”