Influence of alloying additions on grain boundary cohesion of transition metals: First-principles determination and its phenomenological extension

Abstract

The toughness and ductility of ultrahigh-strength alloys is often limited by intergranular embrittlement, particularly under conditions of unfavorable environmental interactions such as hydrogen embrittlement and stress corrosion cracking. Here we investigated the mechanism by which the segregated substitutional additions cause intergranular embrittlement. An electronic level phenomenological theory is proposed to predict unambiguously the effect of a substitutional alloying addition on grain boundary cohesion of metallic alloys, based on first-principles full-potential linearized augmented plane-wave method ͑FLAPW͒ calculations on the strengthening and embrittling effects of the metals Mo and Pd on the Fe grain boundary cohesion. With the bulk properties of substitutional alloying addition A and the matrix element M as inputs, the strengthening or embrittling effect of A at the grain boundary of M can be predicted without carrying out first-principles calculations once the atomic structure of the corresponding clean grain boundary is determined. Predictions of the embrittlement potency of a large number of metals, including the 3d, 4d, and 5d transition metals, are presented for the Fe ⌺3 ͑111͒ and the Ni ⌺5 ͑210͒ grain boundaries. Rigorous FLAPW calculations on the effect of Co, Ru, W, and Re on the Fe ⌺3 ͑111͒ grain boundary and Ca on the Ni ⌺5 ͑210͒ grain boundary cohesion confirm the predictions of our model. This model is expected to be applicable to other high-angle boundaries in general and instructive in the quantum design of ultrahigh-strength alloys with resistance to intergranular fracture.

New Cr-Ni-Base Alloy for High-Temperature Applications Designed on the Basis of First Principles Calculations

“…Figure 2 shows a correlation between the influence of the alloying elements on the bulk and GB cohesion in Cr: the elements from the middle of the series have the most pronounced cohesive strengthening effect on the cohesion while the elements from the beginning and the end of the series have the most pronounced embrittling effect. Such behavior is similar to the result obtained in [8,9] for Ni and seems to be a generic feature for alloying with transition elements in dilute limit in general [39].…”

Computer-aided design of transformation toughened blast resistant naval hull steels: Part I

“…Looking ahead to the projected naval hull material requirements in the year 2020, the primary design objectives motivating this research are the achievement of extreme impact fracture toughness (C v > 85 ft-lbs or 115 J corresponding to fracture toughness, K Id > 200 ksi in 1/2 or 220 MPa m 1/2 and K Ic > 250 ksi in 1/2 or 275 MPa m 1/2 ) at high strength levels of 150-180 ksi (1,030-1,240 MPa) yield strength in weldable, formable plate steels with high resistance to hydrogen stress corrosion cracking (K ISCC /K IC > 0.5) [18,19]. Because of difficulties in measurement of K Id and K Ic fracture toughness at such extreme levels, toughness of prototypes will be assessed by Charpy impact energy (C V ) absorption measurements; details of the K Ic − C V and K Id − C V toughness correlation will be discussed later.…”

Multiscale Modeling of Phase Transformations in Steels

“…Computational materials science now offers tremendous opportunities to formulate models containing fundamental information on the basic atomic mechanisms of microstructure evolution that can be implemented across different length and time scales. [7][8][9] This approach essentially embraces the concept of integrated computational materials engineering (ICME) as a transformational discipline to efficiently develop advanced materials and their incorporation into the design of new products. 10 ICME is considered to be a promising tool to accelerate innovation in the engineering of materials and manufactured products; i.e., it is critical for the steel industry to remain at the forefront of related research and development activities.…”