Agnieszka Szkliniarz

The Chemical Composition and Microstructure of Ti-47Al-2W-0.5Si Alloy Melted in Ceramic Crucibles

In this paper, the technology of melting in induction furnaces with ceramic crucibles was used for production of TiAl-based Ti-47Al-2W-0.5Si alloy. Due to high reactivity of liquid titanium alloys, the melting process was conducted in special crucibles made of stabilised ceramic materials resistant to the aggressive action of these alloys. When characterising the chemical composition and microstructure of Ti-47Al-2W-0.5Si alloy melted in different ceramic crucibles, problems accompanying the melting process were described and conditions for making an alloy with satisfactory purity were determined.

Assessment of Quality of Ti Alloys Melted in Induction Furnace with Ceramic Crucible

In this work, the possibility of melting titanium alloys in vacuum induction furnaces in metal and ceramic crucibles and in ceramic crucibles with coatings deposited by the plasma-spray method or by hand using a brush was evaluated. The effect of the crucible material and the coating material on the chemical composition, microstructure and alloy properties was studied. The main criterion for evaluating the suitability of individual crucibles was the content of oxygen in the molten alloys and of impurities remaining as a result of the reaction of the liquid alloy with the crucible and coating material.

Quantitative Characterization of Microstructure of Ti-47Al-2W-0.5Si Alloy after Melting in Vacuum Induction Furnace

In this paper, the microstructural characteristics of cast TiAl-based intermetallic alloy were conducted, indicating the average grain diameter and interlamellar spacing as the parameters that determine their functional properties. The possibilities of forming these parameters by changing the crystallisation conditions were also shown. Methods for acquisition of images as well as detection of grain boundaries and lamellar precipitations of phases, necessary in the measurement of stereological parameters of the microstructure of these alloys, were presented

Microstructure and Properties of Ti-47Al-2W-0.5Si Cast Alloy

The paper characterized the phase composition, microstructure and selected mechanical properties at room temperature and at temperature corresponding to the expected operating conditions of two-phase Ti-47Al-2W-0.5Si cast alloy melted in a vacuum induction furnace in a special graphite crucibles.

The characteristics of TiAl-based alloys melted in graphite crucibles

ABSTRACT In the paper, the phase composition, microstructure, and selected mechanical and operational properties at room and elevated temperature of a TiAl intermetallic alloy from the TNB group – Ti–45Al–8Nb–0.5(B, C), induction melted in special graphite crucibles, are characterised. Selected properties of this alloy were compared to those of the reference TNB-V2 alloy with similar chemical composition, prepared with technologies currently used in the world. The result of this comparison was a positive recommendation for the proposed melting technology as an alternative to this and other groups of TiAl-based alloys. This paper is part of a thematic issue on Titanium.

Microstructure and Properties of Beta 21S Alloy with 0.2 wt. % of Carbon

Taking into account the high requirements of new structural materials the development of high-strength and high-temperature alloys based on titanium is a subject of great scientific interest. Carbon has usually been regarded as an impurity of titanium alloys. Increasingly however, it begins to play an important role as alloy addition and, taking into account its price, it is consistent with the global cost-cutting trend for production and processing of new alloys with improved properties. The addition of carbon creates new application opportunities for titanium alloys. The relationship between mechanical properties and microstructure of Beta 21S alloy with carbon addition were considered in this study. The alloy was produced traditionally by vacuum induction melting in cold crucible furnace and hot-deformed with further heat treatment. The effect of heat treatment on the conventional strength and creep resistance of researched alloy was also determined.

Effect of Heat Treatment on the Microstructure and Properties of Ti-8Al-1Mo-1V Alloy with Carbon Addition

The paper concerns a new group of titanium alloys with improved properties caused by presence of carbon. The effect of heat treatment processes like annealing, solution treatment and precipitation hardening on the microstructure of Ti-8Al-1Mo-1V alloy with carbon content not exceeding the limit of solubility of carbon in the alpha phase (0.2 wt. %) were presented. The result of hardness test, static tensile test and creep test of research alloy in both annealing and hardening state was showed. The obtained results were referred to the same alloy without carbon. Investigated alloy is characterized by improved tensile strength with comparable plastic properties. The investigated alloy was characterized better creep resistance after duplex annealing treatment than after hardening.

Microstructure and Properties of a New Generation of TiAl Based Alloys

The paper characterized the phase composition, microstructure and selected mechanical properties at room temperature and at temperature corresponding to the expected operating conditions of a new generation of TiAl based alloys melted in a vacuum induction furnace in a special graphite crucibles.

Thermal Stability of Ti-6Al-4V Alloy with Carbon Content

In the paper, the effect of long-term annealing (to 500 h) on the microstructure and hardness of two-phase titanium alloy which represent group of α+β (Ti-6Al-4V) with 0.7 wt. % carbon content was present. The stability of microstructure after long-term annealing was conducted to alloys in hardening state (after solution treatment and aging). Annealing was carried out at a temperature above the operating temperature of commercial titanium alloys without carbon content. The analysis of changes in the microstructure at research range of annealing time indicates its stability, which was confirmed by hardness test of investigated alloys. For comparison to Ti-6Al-4V-0.7C alloy, the microstructure stability research at 420oC was conducted for classical alloy contain no carbon. This alloy was previously subject solution and aging treatment under the same conditions as tested alloy.

Stereological Characterization of TiC Carbides in Bottom Skull after Melting of Ti-6Al-4V-0,5C Alloy in Vacuum Induction Furnace

This paper presents the microstructural characteristics of skull formed during melting of Ti-6Al-4V alloy with 0.5 wt% content of carbon in vacuum induction furnace using water-cooled copper crucible. The microstructure of ingot obtained as a result of skull melting is comprised of TiC carbides evenly distributed in the matrix, which consists of lamellar precipitations of α and β phases. The depth of carbon penetration towards the bottom skull was determined. At the plane section area of bottom skull, three clearly visible zones with diverse area fraction and sizes of carbides that occur in them were found. The effect of area fraction of carbides on hardness of individual zones at the bottom skull with reference to hardness of obtained ingot was also characterized.