A Microstructural and Mechanical Properties Comparison of P/M 718 and P/M TA 718

Abstract

The effects of Ta on phases and mechanical properties in conventional 718 type compositions have not been fully explored. While Ta and Nb have similar atomic sizes, the solubility of Ta in nickel is much greater than that of Nb. This difference in solubility would affect the initial segregation on solidification and subsequent phase reactions. To study the role of Ta in phase reactions and on alloy stability in a homogeneous material, a comparative study of conventional P/M 718 and P/M Ta 7 18 was undertaken. The results of this study showed that the heat treatment used for conventional 7 18 did not produce an significant strengthening phases in Ta 718 and a modified heat treatment was to reci necessa~ p p itate ?/' and 1/ strengthening phases. The ?/' phase in Ta 718 is still present at 1750 F. The r to delta transition in Ta 718 is more sluggish and occurs at higher temperatures than in conventional 718 materials. Data from tensile tests at 1400'F indicates that Ta 718 has a higher temperature capability than conventional 718.

Grain boundary precipitation in Inconel 718 and ATI 718Plus

“…The available materials at this time were not suitable and so there was a requirement for materials with improved properties [1]. These properties included higher strength, greater corrosion resistance and enhanced creep and fatigue properties at higher temperatures.…”

“…This is achieved through the use of the elements aluminium, titanium and niobium [1]. These three elements are used to produce two different primary strengthening precipitates, namely γ and γ .…”

Open charm-bottom scalar tetraquarks and their strong decays

“…Originally proposed to find masses, decay constants, form factors of the conventional mesons and baryons, it was successfully applied to analyze also exotic tetraquark states, glueballs and hybrid qqg resonances in Refs. [25][26][27][28][29]. The QCD two-point sum rule method remains among the fruitful computational tools high energy physics to investigate the exotic states.…”

Structure Stability Study on a Newly Developed Nickel-Base Superalloy - Allvac 718Plus

“…They raised the ratio of (Al+Ti)/Nb and the sum (Al+Ti+Nb) in atomic percentage and developed a compact morphology of γ″ + γ′ heat treatment. In recent twenty years, Xishan Xie and Jianxin Dong at UST Beijing and other researchers such as Keh-Minn Chang also engaged in the major elements modifications such as Al, Ti, Nb adjustment [8~13] and Co, Ta [14,15] additions. The attribute of major elements modification was to enhance the microstructure and mechanical property stability.…”