Effect of Titanium Modification on Microstructure and Impact Toughness of High-Boron Multi-Component Alloy

This work investigated the microstructure and mechanical property of high-boron multi-component alloy with Fe, B, C, Cr, Mo, Al, Si, V, Mn and different contents of Ti. The results indicate that the as-cast metallurgical microstructure of high-boron multi-component alloys consist of ferrite, pearlite and borocarbide. In an un-modified alloy, continuous reticular structure of borocarbide is observed. After titanium addition, the structure of borocarbide changes into a fine and isolated morphology. TiC is the existence form of titanium in the alloy, which acts as the heterogeneous nuclei for eutectic borocarbide. Moreover, impact toughness of the alloy is remarkably improved by titanium modification.

A scalable Al–Ni alloy powder catalyst prepared by metallurgical microstructure control

Metallurgical microstructure control of Al–Ni alloys enabled scalable and facile synthesis of large-area electrodes for alkaline hydrogen evolution catalysts comparable to conventional Pt catalysts.

Mechanism Analysis of a Boiler Economizer Corrosion

Reasons for boiler economizer tube corrosion were discussed based on results of macroscopic inspection, metallurgical microstructure examination, SEM and EDS fracture analysis. Results showed that the tube corrosion was due to sulfur corrosion that resulted in matrix exposure and led to further oxygen corrosion.

Research on the Optimal Design of Soccer Robot Based on the Mechanical Analysis

Leakage causes of branch pipe of unit thermal networks were discussed based on macroscopic observation, chemical composition analysis, metallurgical microstructure inspection, mechanical property tests, SEM and EDS analysis. The experimental results showed that frequent contact of outer pipe wall with corrosion media and thermal fatigue load led to early crack of the pipe. During compression test, the crack propagated under increased compression stress and burst finally. Suggestions were provided to prevent similar events happening.

Analysis on Fracture Causes of Condensate Water Pump Shaft

Failure causes on a condensate pump shaft were discussed by means of macroscopic observation, chemical composition analysis, metallurgical microstructure inspection, mechanical property tests and stress analysis. The experimental results showed that the improper material with disqualified chemical composition, improper microstructure and poor mechanical properties acted as inherent factor. In addition, structure design that led to stress concentration contributed to the failure as external factor. Finally, fatigue fracture happened at the reduce section of the pump shaft.

Fracture of the Leads of Integrated Circuits with TO Package

The Kovar alloy leads broke from two integrated circuits (ICs) with TO (Tin Outline) package. Through the metallurgical microstructure analysis, energy dispersive spectrometer (EDS) analysis and fractography analysis, the failure mode of the leads was found to be stress-corrosion-cracking. After checking the whole plating process, it was found that the residual chloride ions resulted in stress-corrosion-cracking. The chloride ions were absorbed inside the residual organic containment below Ni-plating layer. And a corrective measure was proposed.

Analysis and Suggestions on Leakage of Boiler Low Temperature Reheater

Leakage causes of boiler low temperature reheater were discussed by means of macroscopic inspection, chemical composition analysis, metallurgical microstructure examination, SEM and EDS fracture analysis. Results showed that the reheater leakage occurred for cracks originating from the fillet seam of ear plate. The main causes lie in improper structural design of the ear plate welding directly on the reheater elbow where suffered from complicated stress condition, wall thinning and out-of-round. In addition, as a weak zone, heat effect zone of the fillet welding seam was more likely to crack under fatigue stress for frequent unit start and stop and pipeline vibration. Installation stress existed between the ear plate and support block also contributed to the cracking. Suggestions were provided to avoid similar accident based on the comprehensive analysis of leakage causes.