Laterite steels might be used for alternative armored steels. Their properties can be improved in various ways, such as by heat treatment. This paper reports the influences of tempering temperature on the hardness and microstructure of the modified MIL A-12560/AISI 4340 steels. Samples were austenitized at 1200, 1000, and 800°C and forged at 100, 75, and 50 tons. Mechanical properties consisted of Hardness measurement was conducted by Brinell indentation and metallographic observation was conducted by scanning electron microscopy (SEM). The results showed that increasing forging force until 100 tons can decrease hardness. The formation of the microstructure consists of tempered martensite containing ferrite and dual phase perlite. The presence of void and porous can also decrease hardness. Decreasing austenizing temperature from 1200 °C to 800°C can increase material strength and hardness.

MgB₂/CNT is a promising candidate for superconducting wire application due to its excellent mechanical properties and carbon nanotube’s low density. However, strong interfacial adhesion between the CNT reinforcement and the MgB₂ matrix is difficult to manage. Therefore, this study examines the synthesis and characterization of magnesium diboride (MgB₂) superconductors with carbon nanotubes (CNTs) and tin (Sn) addition. Determining the proper method and combination of CNT & Sn affects MgB₂ superconductors is crucial. Raw materials of magnesium (Mg), boron (B), Sn, and multi-walled carbon nanotubes (MWCNTs) were used for a solid-state reaction process to determine the proper synthesis method and the effect of CNT on superconductors’ critical temperature. Each sample was obtained by weighing the raw material first, followed by hand grinding with agate mortars for 3 hours. The pelletization was then conducted by using a compact pressing machine with a pressure of 350 MPa. The compacted samples were then sintered at 800 °C for 2 hours either through the vacuum or PIST process. Finally, all were characterized, and MgB₂ was discovered to be the dominant phase with minor impurity phases such as MgO, Mg, Mg₂Sn, C, and Sn. Based on SEM morphological analysis, the grain boundaries of sample A1 were more precise than B2. In both, the grain size also varies, and the distribution of elements is uneven. Subsequently, Cryogenic Magnet Characterization indicated that at 40 K, almost all samples possess superconducting characteristics. For future studies, the potential impact of MgB₂ on critical current density (Jc) and magnetic density (Hc) in several commercial applications such as Magnetic Resonance Imaging (MRI), magnetic levitation, and transformers needs to be investigated

Indonesia has the most laterite ore reserves in the world. The element originated from the laterite ore is one of the materials in the steel industry. Despite its plentiful of reserves, laterite steel ore has not been used to its maximum potential. This research aims to overview reduction effect on mechanical properties of laterite steel as a result of heated rolling process with various reduction. The reduction variety used in this research were 30%, 40%, 50%, and 60%. Also, the temperature was 980oC. As a result of this research, the increment of reduction followed by the increment of hardness and firmness level of laterite steel. It is proofed by hardness and tensile test. Firmness of the material increased as the reduction increases. The most optimized mechanical properties obtained by 50% reduction, the hardness number was 280.03 HB, tensile strength 620 MPa, elongation 32%, yield 493.33 MPa. Micro structures which formed in this process are ferrite and pearlite phase with very fine pellet size and even pearlite distribution. Fracture types are brittle and ductile fracture with very fine pellet size.

Magnesium diboride (MgB₂) is a potential superconductor materials that could be applied as superconducting wires due to its relatively high critical temperature. To study the influence of carbon nanotubes (CNT) on MgB₂ wire manufacture, CNT-doped MgB₂ superconducting wires have been fabricated from MgB₂ and CNT powders sheathed in a SS304 stainless steel tube. In the process, the mixtures of MgB₂ and CNT powders were inserted into the SS304 tubes and then were rolled and drawn. The properties of the fabricated superconducting wires were then analyzed through the crystal structure, surface morphology and temperature dependence of resistivity. The addition of CNT did not seem to have a significant influence on the crystal structure of Magnesium diboride. However, the addition of CNT caused the particle size of MgB₂ became smaller. The temperature dependence of resistivity results showed that the critical temperatures were shifting linearly toward low temperatures due to the addition of CNT.