Cailiao gongcheng (Oct 2017)
Preparation of High Quality Ti-6.5Al-1.4Si-2Zr-0.5Mo-2Sn Alloy Powder by Plasma Rotating Electrode Process
Abstract
This research aims to prepare high quality powder of Ti-6.5Al-1.4Si-2Zr-0.5Mo-2Sn,which lays foundation for the following preparation of powder high temperature titanium alloy component.Ti-6.5Al-1.4Si-2Zr-0.5Mo-2Sn alloy ingots were prepared by vacuum arc remelting (VAR). The chemical compositions of ingots were examined. The loss of alloy elements, uniformity of composition, phase composition and microstructure of titanium alloy ingots were analyzed. Then powders were prepared by plasma rotating electrode process (PREP) with different rotating speeds. Alloy powders were sieved into different particle sizes. The relationship between rotating speed and physical and chemical properties of powder was studied. X-ray diffraction(XRD), scanning electron microscope(SEM) and metallurgical microscope(OM) were used to investigate the phase composition, morphology and microstructure of the powder. The results show that the composition distribution of titanium alloy ingot prepared by VAR is uniform and the content of alloy elements meets the requirements of national standard, through a unique pressing electrode. Microstructure of the ingot is lamellar structure with small amounts of silicide particles disperse in the matrix. The size distribution of the powders made by PREP method exhibits the normal distribution. The sphericity of the powder is excellent,and no hollow ball and satellite ball exists. With the increase of rotating speed, the proportion of small particles increases dramatically,the proportion of large particles decreases greatly. The phase composition of powder is mainly α' phase,and it is mainly composed of peritectic and small amount of dendrite structures. Compared with the alloy ingot, the elements of the powders have a slight loss, the content of O is less than 0.1%,which is beneficial to obtain high-performance powder titanium alloy.
Keywords
