<p style="text-align: justify;">This paper describes the difference in the creep rate of pre-strained and no pre-strained samples of superalloy N07080. The primary strengthening mechanism of this superalloy is based on the precipitation of fine and coherent particles of the intermetallic &gamma;' phase Ni₃(Al,Ti) that ensure good creep resistance. In the case of additional strengthening of superalloy N07080 by warm plastic deformation, sometimes required by the automotive industry, its life in creep conditions will be significantly reduced. Performing the partial recrystallization annealing, after solution annealing and warm deformation, and before the final precipitation annealing, leads to a decrease in strength and an increase in the superalloy ductile properties and return of part of the lost creep life due to warm deformation.</p> <p style="text-align: justify;">Because of the shorter lifetime of warm-deformed superalloy N07080 samples, their creep rate is higher than that of those not warm-deformed. The creep rate at 50 % of creep rupture life of superalloy N07080 that warm rolled by 30% deformation (1080&deg;C/8h+30% warm def.+700&deg;C/16h) is 12,9 times higher than the creep rate of the standard heat-treated superalloy. This creep rate reduces with increasing partial recrystallization temperature and for recrystallization temperature 1080&deg;C it reaches values close to those that the superalloy possesses after standard heat treatment (1080&deg;C/8h+700&deg;C/16h).</p>

<p>Steel 17-7PH is austenitic-martensitic steel with high strength, hardness, and resistance to creep, and<br />corrosion. It is designed for aerospace components, but can also be used for other applications that require<br />high strength and corrosion resistance, as well as leaf springs for operation at temperatures up to 316 &deg;C. It<br />can be used in a solution-treated or heat-treated state to obtain a wide range of property values. This<br />paperwork shows that modification of the contents of alloying elements with a narrower interval of Cr, Ni,<br />and Al can be obtained from austenitic-martensitic steel 17-7PH which by, a subsequent heat treatment,<br />can have values of mechanical and chemical properties required for components of an automotive engine.<br />Chromium is an alphagenic alloying element that stabilizes the ferrite region, nickel is a gammagenic<br />alloying element that stabilizes austenite and gives these steels good strength and toughness, even at low<br />temperatures and aluminum increases corrosion resistance in low-carbon corrosion-resistant steels<br />Research has determined the most suitable interval of Cr, Ni, and Al, which in combination with the<br />cryogenic heat treatment RH950 at -50 &deg;C gives the mechanical and chemical properties that meet the<br />requirements for steel with standard chemical composition.</p>

<p>More recently modified stainless steels have been used to produce various structural elements that work in complex operating conditions. Stainless steel X8CrNiS18-9 (standard EN 10088-3) is the most commonly used from the group of austenitic stainless steel in terms of machinability. This steel has high mechanical and working properties thanks to a complex alloying, primarily with elements such as chromium and nickel. The content of sulphur present in the steel from 0.15 to 0.35% improves machinability. However, sulphur at the same time decreases the mechanical properties, particularly toughness. In steel, tellurium stabilizes carbides and reduces the microporosity of the structure. Also, tellurium is now recognized as a powerful sulphur modifier as well as a machinability additive when used in combination with lead and sulphur. This work aims to determine the influence of tellurium on the machinability, corrosion resistance and mechanical properties of the mentioned steel.</p>

Additional strengthening of superalloy N07080 described in this work was achieved by warm rolling. Control of the ratio of strength and ductile properties of the superalloy is possible by appropriate selection of the amount of warm deformation and the appropriate selection of the partial recrystallization temperature. In addition, recrystallization annealing makes it possible to equalize the grain size across the cross section of the warm rolled bars, which before recrystallization differ significantly in size in the central and peripheral parts of the bars.

Magnesium based materials are considered promising biodegradable metals for orthopedic bone implant applications as they exhibit similar density and elastic modulus to that of bone, biodegradability, and excellent osteogenic properties. The use of Mg based biomaterials eliminates the limitations of currently used implant materials such as stress shielding and the need for the second surgery. Recently, the development of Mg-based implants has attracted significant attention. Additive manufacturing is one of the effective techniques to develop Mg based implants. Additive manufacturing which could be named 3D printing is a transformative and rapid method of producing industrial parts with in the acceptable dimensional range. Therefore, recent investigations have tried to apply this method for the development of Mg-based implants. This state-of-the-art review focuses on the additive manufacturing of Mg biodegradable materials and their in-vitro corrosion and degradation, and mechanical properties. The future directions to develop Mg biodegradable materials are reported through summarization of current achievements.

Magnesium has little resistance to corrosion and therefore its production and use are quite limited. The problem of corrosion associated with these alloys has been alleviated to some extent by the advantages obtained from fine coatings. An additional dense barrier against corrosion is created, using coatings obtained from sol-gel. As an alternative for Cr-based conversion coatings, rare-earth elements-based ones are been increasingly investigated for Mg and its alloys due to being eco-friendly. Because of chemical inertness, low friction, and high hardness, diamond-like carbon (DLC) coatings have exhibited the best protection for Mg and its alloys. In this review, we shed light on recent advancements in novel coatings for Mg alloys including hybrid, rare-earth conversion, composite polymeric (polymer composite is a multi-phase material in which reinforcing fillers are integrated with a polymer matrix), and DLC coatings.

Precipitation hardening stainless steel 17-7PH with modified chemical composition was heat treated by modified RH950 condition. In this paper is presented the results of tests of microstructure and mechanical properties of precipitation hardened stainless steel 17-7PH with modified chemical composition, heat treated in modificated RH950 conditions. Regression analysis showed which variables are statistically significant in predicting the value of mechanical properties of the steel 17-7PH chemically modified composition.

Metallic glasses are metastable amorphous structures produced by quenching-rapid cooling technique. Due to very high cooling rates during the production process, it is very difficult to produce homogeneous samples with identical chemical composition. In this paper we will present preliminary results of homogeneity and structure examinations of a CuZrAlY metallic glass ribbon. The ribbon, approximately 1.5 m long and 1 mm wide, was produced using melt spinning technique. Samples from the middle and the end of the ribbon were chosen for further examination. Surface was checked by metallographic and electron scanning microscopy. Chemical composition in different areas of each sample was checked by energy-dispersive X-ray spectroscopy. Electrical resistivity measurements in the temperature range from 80 K to 280 K were also conducted.

Possibilities of the application of new materials in the automotive industry place challenges in front of researchers of our times. Modification of the chemical composition and different variants of heat treatment allows achieving improved mechanical properties. Steel 17-7PH is austenitic martensitic steel with high strength (750-1500 MPa) and hardness (34-49HRC), which is achieved by controlled phase transformation and complex heat treatment of precipitation strengthening. In this paper, through the results of tensile properties of steel 17-7PH for condition TH1050 and modified condition RH 950 obtained at room temperature, the influence of heat treatment will be presented.