ABSTRACT The attempt to face the limitations of wood-based materials, especially concerning the relationship with water, is still a considerable gap in research on this subject. The present work proposes the accomplishment of thermal treatment in fiberboard-type hardboard, using different temperatures and times, to evaluate the effect on the physical-mechanical properties. The parameters of the heat treatment were temperatures of 120 and 160 °C and times of 20 and 40 min. The hardboards were individually heat treated in a kiln. The characterization was performed from physical tests such as bulk density, moisture content, water absorption (2 and 24 h), thickness swelling (2 and 24 h); and mechanical properties of flexural strength. The treatment with a temperature of 160 °C for 40 min showed the lowest values of water absorption in 24 h (34%). Thickness swelling was lower compared to control, for all the treatments applied. Regarding flexural strength, the treatment that adopted the 160 °C for 20 min showed the highest MOR value (26.3 MPa). In general, the performance of heat treatments positively influenced the physical and mechanical properties of the hardboards, being an interesting alternative in the development of products for applications in internal environments.

ABSTRACT Economic development based on cleaner industrial technologies has been increasingly studied in recent years. Cementitious composites reinforced with lignocellulosic fibers can be a sustainable alternative for use in engineering. The study aimed to evaluate the technological properties of cementitious composites produced from natural and industrial coconut fiber to compare the reinforcement with wood particles. Physical tests (density, water absorption, and thickness swelling) and mechanical tests (static bending) were carried out in four treatments, which varied the fiber and cement contents. It was found that treatment with natural coconut fiber had the lowest density value, 0.59 g/cm3, and treatment with industrial coconut fiber had the lowest water absorption value for the times and times of 2 and 24 h, 0.19, and 0.38%, respectively, and the treatment with wood particles, the highest values of modulus of elasticity and rupture, 1,897 MPa and 2.44 MPa. The study of the use of lignocellulosic materials as protection in cementitious composites is essential for applications in building constructions to reduce the environmental impacts generated by the generation of waste and use of non-renewable materials and to promote sustainable development.

ABSTRACT Were characterized microstructurally and mechanically the Ti-6Aℓ-4V alloy obtained through powder metallurgy in an uncontrolled atmosphere, varying the sintering parameters, arose. The samples were compacted in a uniaxial press at 874 MPa, 999 MPa, and 1124 MPa, and sintered without a protective atmosphere or vacuum, at 675 °C, 750 °C, and 850 °C. When sintering the material, the oxides influenced the results due to titanium’s high affinity for interstitial elements, promoting increased density and high hardness values. Based on the results, the treatment carried out at a pressure of 1124 MPa and a temperature of 750 °C showed the highest hardness in the beta phase (β), with a value of 1165.1 HV. In the alpha phase (α), the highest value was 1321.3 HV, presented by the treatment performed at a pressure of 999 MPa and a temperature of 850 °C. The high hardness values observed in the alloy are associated with the reinforcement promoted by the dissolution of Fe atoms. Materials with high hardness values use in the aerospace and biomedical industries, which always look for better mechanical resistance results, thus increasing their products’ useful life and applicability.

RESUMO Foram caracterizadas micro estruturalmente e mecanicamente a liga Ti-6Aℓ-4V obtida através da metalurgia do pó em atmosfera não controlada variando os parâmetros de sinterização. As amostras foram compactadas em uma prensa uniaxial à 874 MPa, 999 MPa e 1124 MPa, e sinterizadas sem atmosfera protetora ou vácuo, nas temperaturas de 675 °C, 750 °C e 850 °C. Ao sinterizar o material, houve influência dos óxidos nos resultados devido à alta afinidade que o titânio tem por elementos intersticiais, promovendo um aumento na densidade e elevados valores de dureza. A partir dos resultados verificou-se que o tratamento realizado na pressão de 1124 MPa e temperatura de 750 °C foi o que apontou a maior dureza na fase beta (β), sendo o valor de 1165,1 HV. Na fase alfa (α), o maior valor foi de 1321,3 HV, apresentado pelo tratamento realizado na pressão de 999 MPa e temperatura de 850 °C. Os elevados valores na dureza observados na liga estão associados ao reforço promovido pela dissolução átomos de Fe. Materiais com elevada dureza possuem uma vasta aplicação nas indústrias aeroespaciais e biomédicas, que buscam sempre por melhores resultados de resistência mecânica, aumentando assim a vida útil e a aplicabilidades de seus produtos.