Ceramic-reinforced HEA matrix composites exhibiting an excellent combination of mechanical properties

CoCrFeNi is a well-studied face centered cubic (fcc) high entropy alloy (HEA) that exhibits excellent ductility but only limited strength. The present study focusses on improving the strength-ductility balance of this HEA by addition of varying amounts of SiC using an arc melting route. Chromium present in the base HEA is found to result in decomposition of SiC during melting. Consequently, interaction of free carbon with chromium results in the in-situ formation of chromium carbide, while free silicon remains in solution in the base HEA and/or interacts with the constituent elements of the base HEA to form silicides. The changes in microstructural phases with increasing amount of SiC are found to follow the sequence: fcc → fcc + eutectic → fcc + chromium carbide platelets → fcc + chromium carbide platelets + silicides → fcc + chromium carbide platelets + silicides + graphite globules/flakes. In comparison to both conventional and high entropy alloys, the resulting composites were found to exhibit a very wide range of mechanical properties (yield strength from 277 MPa with more than 60% elongation to 2522 MPa with 6% elongation). Some of the developed high entropy composites showed an outstanding combination of mechanical properties (yield strength 1200 MPa with 37% elongation) and occupied previously unattainable regions in a yield strength versus elongation map. In addition to their significant elongation, the hardness and yield strength of the HEA composites are found to lie in the same range as those of bulk metallic glasses. It is therefore believed that development of high entropy composites can help in obtaining outstanding combinations of mechanical properties for advanced structural applications.Financial support from the Higher Education Commission of Pakistan (HEC NRPU 6019) is acknowledged. FEDER National funds FCT under the project CEMMPRE, ref. “UIDB/00285/2020” is also acknowledged.info:eu-repo/semantics/publishedVersio

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A field trial was conducted at the Experimental Farms of Pir Meher Ali Shah Agriculture University, Rawalpindi during Rabi season, 2004 to study the effect of spatial arrangements and weeding techniques on weeds and yield of wheat. The experiment was laid out in randomized complete block design with two factors under split plot arrangement having three replications. The spatial arrangements were comprised of 15 cm, 22.5 cm and 30 cm apart rows and there were six weeding techniques viz. weeding check was included for comparison, hand weeding (weed free), chemical control (by application of Buctril Super @ 750 ml ha -1 ), bar-harrow 2-way, hoe and barharow 1-way. Hand weeding and chemical control with different spatial combinations showed significant effects on weed density, weed mortality percentage, weed biomass and grain yield. Spatial arrangement of 15 cm significantly decreased the weed biomass and enhanced grain yield. The interaction between weeding techniques with spatial arrangements was found significant for weed biomass and grain yield. The highest wheat crop yields of 5448 and 5970 kg ha -1 were achieved by using hand weeding and chemical control weeding techniques along with 15 cm spatial arrangement. These treatments caused significant increase of 133.93 % and 113.47% respectively over weedy check with 30 cm spacing

Biofortification of wheat with zinc through zinc fertilization in seven countries

Aim Zinc (Zn) fertilization is an effective agronomic tool for Zn biofortification of wheat for overcoming human Zn deficiency. But it still needs to be evaluated across locations with different management practices and wheat cultivars, since grain Zn concentrations may be significantly affected by locations, cultivars and management. Materials Field experiments were conducted over 3 years with the following four Zn treatments: nil Zn, soil Zn application, foliar Zn application and soil + foliar Zn application to explore the impact of Zn fertilization in Zn biofortification of wheat. The experiments were conducted at a total of 23 experimental site-years in China, India, Kazakhstan, Mexico, Pakistan, Turkey and Zambia. Results The results showed that foliar Zn application alone or in combination with soil application, significantly increased grain Zn concentrations from 27 mg kg(-1) at nil Zn to 48 and 49 mg kg(-1) across all of 23 site-years, resulting in increases in grain Zn by 84 % and 90 %, respectively. Overall, soil Zn deficiency was not a growth limiting factor on the experimental sites. A significant grain yield increase in response to soil Zn fertilization was found only in Pakistan. When all locations and cropping years are combined, soil Zn fertilization resulted in about 5 % increase in grain yield. Foliar Zn application did not cause any adverse effect on grain yield, even slightly improved the yield. Across the 23 site-years, soil Zn application had a small effect on Zn concentration of leaves collected before foliar Zn application, and increased grain Zn concentration only by 12 %. The correlation between grain yield and the effectiveness of foliar Zn application on grain Zn was condition dependent, and was positive and significant at certain conditions. Conclusion Foliar Zn application resulted in successful biofortification of wheat grain with Zn without causing yield loss. This effect of Zn fertilization occurred irrespective of the soil and environmental conditions, management practices applied and cultivars used in 23 site-years. Foliar Zn fertilizer approach can be locally adopted for increasing dietary Zn intake and fighting human Zn deficiency in rural areas

Biofortification of wheat with zinc through zinc fertilization in seven countries

Aim Zinc (Zn) fertilization is an effective agronomic tool for Zn biofortification of wheat for overcoming human Zn deficiency. But it still needs to be evaluated across locations with different management practices and wheat cultivars, since grain Zn concentrations may be significantly affected by locations, cultivars and management. Materials Field experiments were conducted over 3 years with the following four Zn treatments: nil Zn, soil Zn application, foliar Zn application and soil + foliar Zn application to explore the impact of Zn fertilization in Zn biofortification of wheat. The experiments were conducted at a total of 23 experimental site-years in China, India, Kazakhstan, Mexico, Pakistan, Turkey and Zambia. Results The results showed that foliar Zn application alone or in combination with soil application, significantly increased grain Zn concentrations from 27 mg kg(-1) at nil Zn to 48 and 49 mg kg(-1) across all of 23 site-years, resulting in increases in grain Zn by 84 % and 90 %, respectively. Overall, soil Zn deficiency was not a growth limiting factor on the experimental sites. A significant grain yield increase in response to soil Zn fertilization was found only in Pakistan. When all locations and cropping years are combined, soil Zn fertilization resulted in about 5 % increase in grain yield. Foliar Zn application did not cause any adverse effect on grain yield, even slightly improved the yield. Across the 23 site-years, soil Zn application had a small effect on Zn concentration of leaves collected before foliar Zn application, and increased grain Zn concentration only by 12 %. The correlation between grain yield and the effectiveness of foliar Zn application on grain Zn was condition dependent, and was positive and significant at certain conditions. Conclusion Foliar Zn application resulted in successful biofortification of wheat grain with Zn without causing yield loss. This effect of Zn fertilization occurred irrespective of the soil and environmental conditions, management practices applied and cultivars used in 23 site-years. Foliar Zn fertilizer approach can be locally adopted for increasing dietary Zn intake and fighting human Zn deficiency in rural areas