Influence of the Deep Cryogenic Treatment on AISI 52100 and AISI D3 Steel’s Corrosion Resistance

The effect of deep cryogenic treatment (DCT) on corrosion resistance of steels AISI 52100 and AISI D3 is investigated and compared with conventional heat-treated counterparts. DCT’s influence on microstructural changes is subsequently correlated to the corrosion resistance. DCT is confirmed to reduce the formation of corrosion products on steels’ surface, retard the corrosion products development and propagation. DCT reduces surface cracking, which is considered to be related to modified residual stress state of the material. DCT’s influence on each steel results from the altered microstructure and alloying element concentration that depends on steel matrix and type. This study presents DCT as an effective method for corrosion resistance alteration of steels

Coupled role of alloying and manufacturing on deep cryogenic treatment performance on high-alloyed ferrous alloys

This study focuses on influence of alloying content and type of manufacturing on the effectiveness of deep cryogenic treatment (DCT) on properties of selected high-alloyed ferrous alloys (HAFA): EN HS6-5-2, EN HS6-5-2-5, EN HS6-5-3 and EN HS12-1-4. In order to evaluate the dependency of DCT performance on chemical composition and manufacturing type, the microstructure, hardness, impact and fracture toughness and fatigue properties were analyzed. Additionally, the fatigue data was evaluated using an adapted strain-life model in order to understand the unique effects of DCT with selected factors and provide a model for estimating the fatigue limit of DCT HAFA. The study indicates that DCT affects carbide precipitation, size and morphology of nanocarbides, average distance between carbides and nanocarbides, as well as the base matrix (martensitic laths). The induced microstructural changes cause an overall positive change of mechanical properties in selected HAFA, which correlates well with individual alloying and manufacturing differences. Overall, DCT has greater effect on wrought HAFA than powder metallurgy manufactured HAFA, at which high content of W and Co generally degenerates the DCT induced microstructure modifications

Macro- and micro-strain in GaN nanowires on Si(111)

We analyze the strain state of GaN nanowire ensembles by x-ray diffraction. The nanowires are grown by molecular beam epitaxy on a Si(111) substrate in a self-organized manner. On a macroscopic scale, the nanowires are found to be free of strain. However, coalescence of the nanowires results in micro-strain with a magnitude from +-0.015% to +-0.03%.This micro-strain contributes to the linewidth observed in low-temperature photoluminescence spectra