Effect of cycling heat treatment on the microstructure,phase,and compression behaviour of directed energy deposited Ti-Mo alloys

In this study,the effect of triple-cycling heat treatment on the microstructure,phase,and compression behaviour of directed energy deposited(DED)Ti-7Mo alloy was investigated with a focus on a non-equilibrium to equilibrium microstructure transition.As a result of thermal accumulation,in situ cycling,and rapid solidification,the as-deposited sample presents a continuous gradient microstructure withα-Ti in the top region andα+βin the bottom region.After the triple-cycling heat treatment,theα+βTi at the bottom region,which is non-equilibrium,changes to a state of equilibrium nearα-Ti.Meanwhile,the microstructure becomes more uniform throughout the entire sample.The morphology of theα-Ti phase changes from acicular to a short rode-like shape with increases in the number of dimensions.In terms of the mechanical properties,both the microhardness and compression properties were improved,particularly with respect to the fracture characteristics.The heat-treated sample possesses a much higher ductility than the brittle fractural behaviour.This work provides new insights into the microstructure and property optimisation and homogenisation of DED-processed Ti-based components with cycling heat treatment.

Selective scission of glucose molecule by a Pd-modulated Co-based catalyst for efficient CO_(2)reduction under mild conditions

Combining terrestrial biomass as the reductant with submarine-type hydrothermal environments for CO_(2)reduction represents a possible approach for novel energy production systems that sustainably circulate carbon.However,increasing the reductive power of biomass is the main limitation of this potential method.Herein,we demonstrate that Co-doped with small amounts of Pd enhances the reduction of CO_(2)by selectively producing an active intermediate from carbohydrates.This catalytic reaction utilized glucose as a reductant to achieve high formate production efficiency(458.6 g kg^(-1))with nearly 100%selectivity with 7.5 wt%Pd1Co_(20)/γ–Al_(2)O_(3)at a moderate temperature of 225℃.The regulation of the electronic structure of the catalytic Co surface by the dopant Pd plays a key role in promoting the C–C bond cleavage of glucose and hydrogen transfer for CO_(2)reduction.The findings presented here indicate that biomass can serve as the hydrogen source for CO_(2)reduction and provide insight into the potential utilization of CO_(2)in sustainable industrial applications.

Interfacial Characteristics and Mechanical Behavior of Hybrid Manufactured AlSi10Mg–Al6061 Bimetal via Selective Laser Melting and Forging

Hybrid manufacturing(HM)uses additive manufacturing(AM)techniques to prepare complex or fine structures on traditional processing parts,which can fully utilize the advantages of AM to form complex parts,and the high efficiency and low cost of conventional processing methods in manufacturing regular components.A bimetal material was produced by selective laser melting(SLM)of AlSi10Mg on the deformed Al6061 alloy substrate in this study.Firstly,the interface characteristics of the two alloys were studied.The results show that a metallurgical interface with a thickness of 100–200μm was formed as the result of the Marangoni convection during SLM preparation.In detail,the circular flow in the melt pool at the interface led to the dilution of alloying elements and the change of microstructure.Moreover,a suitable first-layer thickness can eff ectively suppress the hot cracks at the interfacial region.Based on the optimized results,the hybrid manufactured samples with diff erent SLM processed volume ratios(SLM-part)to the substrate were prepared to study the mechanical properties and the deformation behavior of hybrid parts.The results show that the volume ratio of the SLM-part to the substrate had an influence on the strength and the elasto-plastic behavior by aff ecting the distribution of plastic deformation.