Welding Metallurgy of
01 Jan 1987-
About: The article was published on 1987-01-01 and is currently open access. It has received 991 citations till now. The article focuses on the topics: Welding.
Citations
More filters
TL;DR: In this paper, the use of a localized molten environment and near-eutectic mixing of elemental powders has led to the formation of nanocomposite microstructures composed of a nickel-rich intermetallic compound interspersed among a binary alloy matrix.
Abstract: Elastocaloric cooling, a solid-state cooling technology, exploits the latent heat released and absorbed by stress-induced phase transformations. Hysteresis associated with transformation, however, is detrimental to efficient energy conversion and functional durability. We have created thermodynamically efficient, low-hysteresis elastocaloric cooling materials by means of additive manufacturing of nickel-titanium. The use of a localized molten environment and near-eutectic mixing of elemental powders has led to the formation of nanocomposite microstructures composed of a nickel-rich intermetallic compound interspersed among a binary alloy matrix. The microstructure allowed extremely small hysteresis in quasi-linear stress-strain behaviors-enhancing the materials efficiency by a factor of four to seven-and repeatable elastocaloric performance over 1 million cycles. Implementing additive manufacturing to elastocaloric cooling materials enables distinct microstructure control of high-performance metallic refrigerants with long fatigue life.
177 citations
TL;DR: In this article, the evolution of grain morphology during solidification of a moving aluminum alloy pool is simulated by considering heat transfer, flow of liquid metal in the molten pool and solidification parameters.
174 citations
Cites background or result from "Welding Metallurgy of"
...The maximum value of cooling rate is at the weld centerline which is consistent with the observation reported in the literature [16], and is zero at the edge of theweld....
[...]
...features are inversely correlated with the local cooling rates [16]....
[...]
...Equiaxed grains also form and coexist with columnar grains under some welding conditions [10,16]....
[...]
TL;DR: In this paper, the authors explored an evolution of a microstructure in AISI 420 martensitic stainless steel during selective laser melting and found that during manufacturing a partitioning and austenite reversion took place, owing to the thermal cycling of the inner regions during manufacturing.
173 citations
Cites background from "Welding Metallurgy of"
...have the same crystallographic orientation, and grew along the b100N crystallographic direction [16,18]....
[...]
15 Feb 2010-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, a microstructural change after laser welding and its effect on the tensile and fatigue properties in dual phase (DP) steels has been evaluated for automotive applications due to their higher tensile strength, better initial work hardening along with larger elongation compared to conventional grade of steels.
Abstract: To reduce fuel consumption and greenhouse gas emissions, dual phase (DP) steels have been considered for automotive applications due to their higher tensile strength, better initial work hardening along with larger elongation compared to conventional grade of steels. In such applications welding and joining have to be involved, which would lead to a localized alteration of materials and create potential safety and reliability issues under cyclic loading. The aim of this investigation was to evaluate microstructural change after laser welding and its effect on the tensile and fatigue properties in DP600 steel. The welding resulted in a significant increase of hardness in the fusion zone, but also the formation of a soft zone in the outer heat-affected zone (HAZ). While the ductility decreased after welding, the yield strength increased and the ultimate tensile strength remained almost unchanged. Fatigue life at higher stress amplitudes was almost the same between the base metal and welded joints despite slightly lower fatigue limit after welding. Tensile fracture and fatigue failure at higher stress amplitudes occurred at the outer HAZ. Fatigue crack initiation was observed to occur from the specimen surface and crack propagation was characterized by the characteristic mechanism of striation formation. Dimples and deformation bands were observed in the fast propagation area.
167 citations
Additional excerpts
...Similar results were presented in [21]....
[...]
TL;DR: The microstructure of metals depends on the additive manufacturing (AM) process and the process parameters, and experimentation on different process parameters for different materials is costl... as discussed by the authors.
Abstract: The microstructure of metals depends on the additive manufacturing (AM) process and the process parameters. However, experimentation on different process parameters for different materials is costl...
166 citations
Cites background from "Welding Metallurgy of"
...Cellular dendrites are formed when the cooling is fast, while slower cooling rates allow formation of secondary dendrite arm (Kou 2003)....
[...]
...rates allow formation of secondary dendrite arm (Kou 2003)....
[...]
References
More filters
TL;DR: In this article, the state of the art in selective laser sintering/melting (SLS/SLM) processing of aluminium powders is reviewed from different perspectives, including powder metallurgy (P/M), pulsed electric current (PECS), and laser welding of aluminium alloys.
1,172 citations
TL;DR: In this article, the authors show that the pre-existing dislocation network, which maintains its configuration during the entire plastic deformation, is an ideal modulator that is able to slow down but not entirely block the dislocation motion.
557 citations
TL;DR: In this article, the fundamental understanding of structure-properties relationship in automotive steels resistance spot welds is discussed. And a brief review of friction stir spot welding, as an alternative to RSW, is also included.
Abstract: Spot welding, particularly resistance spot welding (RSW), is a critical joining process in automotive industry. The development of advanced high strength steels for applications in automotive industry is accompanied with a challenge to better understand the physical and mechanical metallurgy of these materials during RSW. The present paper critically reviews the fundamental understanding of structure–properties relationship in automotive steels resistance spot welds. The focus is on the metallurgical characteristics, hardness–microstructure correlation, interfacial to pullout failure mode transition and mechanical performance of steel resistance spot welds under quasi-static, fatigue and impact loading conditions. A brief review of friction stir spot welding, as an alternative to RSW, is also included.
369 citations
TL;DR: In this article, a unified equation to compute the energy density is proposed to compare works performed with distinct equipment and experimental conditions, covering the major process parameters: power, travel speed, heat source dimension, hatch distance, deposited layer thickness and material grain size.
369 citations
TL;DR: This study attempted to predict solidification defects by DNN regression with a small dataset that contains 487 data points and found that a pre-trained and fine-tuned DNN shows better generalization performance over shallow neural network, support vector machine, and DNN trained by conventional methods.
314 citations