Characterization of β-Ti alloy prepared by SLM method

Selective laser melting (SLM) technology has strict demand to its powder materials which is needed to be spread evenly and conducted laser sintering layer by layer. Therefore, the uniformity and flatness of powder bed are the basic conditions for processing. Ball milling is an important composite powder preparation process of SLM. Three kinds of ball milling processes, dry ball milling, wet ball milling and hollow milling with various parameters are adopted to prepare TC4 / TiB 2 composite powder. It is concluded that a milling time 8 h at a speed of 230 rpm without milling ball is proved the optimal working condition to make the composite powder maintain good spherical shape and ensure the mixing uniformity. The mechanism of three kinds of powder mixing effects is revealed by analyzing the dynamic relationship and hardness of the milling ball, TC4 and TiB 2 particle. This work provides an important reference for the preparation of high quality TC4 / TiB 2 composite powder for SLM.Ball Milling Powder Mixing TC4 / TiB 2 composite powder Selective Laser Melting

Methods and Mechanism of Powder Mixing for Selective Laser Melting

Yang¹,

Xie²,

Zhao³

et al. 2022

Partial Substitution of Mn by Al in the Cocrfenimnxal20-X (X=5, 10, 15) High Entropy Alloy Prepared of Mechanical Alloying and Spark Plasma Sintering

Thürlová¹,

Průša²

2022

High-entropy alloys are known to possed good mechanical properties which are usually related to the preparation technique. In this work, the CoCrFeNiMn X Al 20-X (X=5, 10, 15) alloys were prepared by a combination of mechanical alloying (MA) and compacted via spark plasma sintering (SPS). Such prepared materials were examined for their phase composition and microstructure. Furthermore, their mechanical properties as a result of the content of Mn/Al were determined. It was found, that the partial substitution of Mn by Al lead to increasing the volume content of the solid solution with BCC crystallographic lattice within the ultrafine-grained microstructure of such prepared materials. Moreover, increasing the Al content within the alloy lead also to the improvement of the mechanical properties. The CoCrFeNiMn5Al15 alloy reached the best properties of all the alloys showing compressive strength of 2496 MPa and having a hardness of 668 HV 1.

Analysis of Cutting Forces with Application of the Discrete Wavelet Transform in Titanium Ti6Al4V Turning

Karolczak¹

2023

The paper presents the possibilities of using the wavelet transform to filter the cutting force signal. Tests were carried out by dry turning on the Ti6Al4V alloy with variable cutting parameters. Four blades with different nose geometry and coatings were used. From the recorded waveforms, the mean values of the force component Fc and the load stability coefficient kn were calculated. The measured force waveforms were filtered with Daubechies 4 (db4) and Daubechies 6 (db6) wavelets. From the ratio of the load stability after filtration to the load stability before filtration, the noise and disturbance values generated during the turning of the tested alloy and the force measurement were estimated. The research conducted shows how the machining conditions affect the forces and stability values, and thus also the variability of the cutting edge load when turning a titanium alloy. They also show the effectiveness of the Discrete Wavelet Transform (DWT) in separating the noise from the force signal.