افزودن تیتانیم روی فولاد کم آلیاژ استحکام بالا Effect of Titanium Addition on HSLA Steel

Study on the Mechanism of Strengthening and Toughening Effect

 of Titanium Addition on HSLA Steel 

مطالعه‌ی مکانیزم استحکام‌بخشی و اثر چقرمه‌سازی افزودن تیتانیم روی فولاد HSLA

ABSTRACT

Based on the determination of load variation against deflection by means of Instrumented Charpy Impact testing, the impact energy distribution of the High Strength Low Alloy (HSLA) steel containing Nb, Ni and Ti for pressure vessels at low temperature has been quantitatively studied. The total impact energy Et could be divided into two parts, Ei  and Ep. Ei is related to the base strength of the material in terms of the grain size and alloy addition, which is also found to be less influenced by the holding time of normalization process at 910℃. Whereas, Ep of Ni-Nb-Ti HSLA steel is strongly linked to the period of holding time. Thermodynamic kinetic investigation was  carried out to study the strengthening mechanism with metallurgical microstructure analysis. 

 

رفتار خزشی آلیاژ آلومینیوم - تیتانیوم

Creep behavior of Ti-6Al-4V from 450°C to 600°C

رفتار خزشی Ti-6Al-4V از 450  تا 600 درجه سانتیگراد

ABSTRACT

We present in this paper the creep behavior of Ti-6Al-4V from 450°C to 600°C under applied stress from 100 MPa to 500 MPa. Creep behavior is studied analyzing creep damage after tests and calculating stress exponent (n) and activation energy (Q). Operating creep deformation mechanisms characterization is possible by analyzing crept microstructure by TEM. A comparison of n and Q values with values from literature and a correlation with TEM micrographs will lead us to a discussion about operating creep deformation mechanisms.

 

ریزساختار و خواص مکانیکی آلیاژ تیتانیوم پس از عملیات حرارتی

Microstructure and mechanical properties of 

TC21 titanium alloy after heat treatment 

ریزساختار و خواص مکانیکی آلیاژ تیتانیوم TC21 پس از عملیات حرارتی

ABSTRACT

Microstructure evolutions during different heat treatments and influence of microstructure on mechanical properties of TC21 titanium alloy were investigated. The results indicate that the excellent mechanical properties can be obtained by adopting air cooling after forging followed by heat treatment of (900 °C, 1 h, AC)+(590 °C, 4 h, AC). Deformation in single β field produces pan-like prior β grains, while annealing in single β field produces equiaxed prior β grains. Cooling rate after forging or annealing in single β field and the subsequent annealing on the top of α+β field determine the content and morphology of coarse α plates. During aging or the third annealing, fine secondary α plates precipitate. Both ultimate strength and yield strength decrease with the content increase of coarse α plates. Decreasing effective slip length and high crack propagation resistance increase the plasticity. The crisscross coarse α plates with large thickness are helpful to enhance the fracture toughness.

 

آندایزینگ و عملیات حرارتی تیتانیوم متخلخل

Effects of anodizing parameters and heat treatment on 

nanotopographical features, bioactivity, and cell culture 

response of additively manufactured porous titanium 

اثر پارامترهای آندایزینگ و عملیات حرارتی بر نانو عوارض سطحی، زیست‌فعالی

و پاسخ کشت سلول در تیتانیوم متخلخل ساخته‌شده به روش افزایشی

ABSTRACT

Anodizing could be used for bio-functionalization of  the surfaces of  titanium alloys. In this study, we use anodizing for creating nanotubes on the surface of porous titanium alloy bone substitutes manufactured using selective laser melting. Different sets of anodizing parameters (voltage: 10 or 20 V anodizing time: 30 min to 3 h) are used for anodizing porous titanium  structures that were later heat treated at 500o  C. The nanotopographical features are examined  using electron microscopy while the bioactivity of anodized surfaces is measured using  immersion tests in the simulated body fluid (SBF).

 

رفتار قالب پرکنندگی مذاب های تیتانیوم Mold-filling behavior of titanium melts in vertically rotating molds

Effect of centrifugal and Coriolis forces on

the mold-filling behavior of titanium melts in vertically rotating molds

اثرات نیروهای گریز از مرکز و نیروهای کوریولیس بر رفتار قالب پرکنندگی مذاب های تیتانیوم

در قالب هایی که به صورت عمودی می چرخند

ABSTRACT

The vertical centrifugal-casting technique is widely used in the manufacture of various irregularly-shaped castings of advanced structural alloys with thin walls, complex shapes and/or large sizes. These castings are used in the increasing applications in aero-space/aviation industries, human teeth/bone repairs with near-net shaped components, etc. In a vertically rotating casting system, the mold-filling processes of alloy melts, coupled with solidification-heat transfer, may be much more complicated, because they are driven simultaneously by gravity, centrifugal and Coriolis forces. In the present work, an N-S/VOF-equations-based model, solved using a SOLA-VOF algorithm, under a rotating coordinate system was applied to numerically investigate the impacts of centrifugal and Coriolis forces on metallic melt mold-filling processes in different vertical centrifugal-casting configurations with different mold-rotation rates using an authors' computer-codes system. The computational results show that the Coriolis force may cause remarkable variations in the flow patterns in the casting-part-cavities of a large horizontal-section area and directly connected to the sprue via a short ingate in a vertical centrifugal-casting process. A "turn-back" mold-filling technique, which only takes advantage of the centrifugal force in a transient rotating melt system, has been confirmed to be a rational centrifugal-casting process in order to achieve smooth and layer-by-layer casting-cavities-filling control. The simulated mold-filling processes of Ti-6AI-4V alloy melt, in a vertical centrifugal-casting system with horizontally-connected plate-casting cavities, show reasonable agreement with experimental results from the literature.

 

ورق های تیتانیوم EBW به عنوان ماده ای برای قطعات کشیده شده

EBW  titanium  sheets  as  material  for  drawn  parts

ورق های تیتانیوم EBW به عنوان ماده ای برای قطعات کشیده شده

ABSTRACT

The growing demand for high strength, lightweight and corrosion-resistant drawn parts has created increasing interest in the use of titanium and its alloys. Additional benefits may result from the use of tailor-welded blanks, allowing for significant savings in material, and the possibility of applying higher strength sheets exactly where needed. When forming welded blanks, it is necessary to overcome many technological barriers which are not reflected in technical literature. Therefore, some prior experience in numerical simulations is needed before embarking on further studies of welded blanks formability. For this purpose, it is necessary to determine the mechanical parameters of the base materials, as well as the fusion and heat-affected zones.

 

ارزیابی ساختار در اتصال نفوذی آلیاژ تیتانیوم/فولاد زنگ نزن

THE EVOLUTION CHARACTERISTICS AND NUMERICAL
ANALYSIS OF DIFFUSION BONDING INTERFACE
STRUCTURE OF TITANIUM ALLOY/Cu/STAINLESS STEEL

ارزیابی خصوصیات و آنالیز عددی ساختار در فصل مشترک اتصال نفوذی آلیاژ تیتانیوم/فولاد زنگ نزن

ABSTRACT

Carries on the investigation to the titanium alloy/Cu/stainless steel intermetallic compound of bonding interface in the meantime, to make a thermodynamic model of the interface element diffusion to have a numerical simulation of the diffusion distance and diffusion temperature, time. Using analysis methods of stretching test, microhardness test, SEM and EDS, to investigate and research the mechanical properties, the interface structure characteristic, the principal element atomic diffusion mechanism of joints thermal simulation and the vacuum diffusion bonding of Ti-6Al-4V/Cu/304, the reacting phases are produced and the distribution range . The results show that when bonding prssere is 5.0 MPa ، the joints tensile strength first increase and then decreases, with bonding temperature and time rising, When bonding temperature is 1223K, bonding time is 3.6 ks, there is a maximum tensile strength that is 162.73 MPa. However, it will is disadvantageous to performance of the joints, when bonding temperature and time extended overly. It formed multi-phase transition organizations by solid solution, intermetallic compounds in the bonding interface, such as Ti2Cu, TixCuy , Ti2Fe, TiFe2 and TiFe. Effect of TixFey on strength of the joints is slightly inferior the TixCuy compound. The fracture is mainly by the titanium alloy side region III for the source dehiscence, developing in the weak diffusion layer.

توسعه مواد کاربید تیتانیوم و هافنیوم فوق سخت

on Development of Ultrahard Hafnium and Titanium Carbide Materials 

توسعه مواد کاربید تیتانیوم  و هافنیوم فوق سخت

ترجمه فصل اول ودوم

ABSTRACT

A mixture of HfC and Itc powders and a (Hf,Ti)C powder have been hot pressed with 4wt% Ni , In the absence of Ni the hot pressed temperature was 2000 C and in the presence of Ni 1650 C . The pressure of 30 MPa was applied in both cases . The starting powders were substoichiometric as deduced from XRD spectra analyses , and the (Hf,Ti)C powders consisted of a range of composition , as indicated by the width of the XRD peaks. In the absence of Ni the powders sintered without the formation of a liquid phase.In the case of HfC and TiC mixture , high – energy dry milled HfC + TiC +C black powder sintering occurred with simultaneous formation of (Hf,Ti)C Solid solution . In the presence of Ni,sintering occurred with the formation of a liquid phase . the volume fraction of the liquid phase formed was sufficieng to yield a low porosity . grain growth was less than in the case of material sintered without Ni,Probably just on account of lower sintering temperature . In the case of high – energy dry milled the reduction in particle size was observed.

ماشین کاری تیتانیوم و آلیاژهای آن

MACHINING TITANIUM AND ITS ALLOYS

ماشین کاری تیتانیوم و آلیاژهای آن 

ABSTRACT

Titanium and its alloys are attractive materials due to their unique high strength-weight ratio that is maintained at elevated temperatures and their exceptional corrosion resistance. The major application of titanium has been in the aerospace industry. However, the focus shift of market trends from military to commercial and aerospace to industry has also been reported. On the other hand, titanium and its alloys are notorious for their poor thermal properties and are classified as difficult-to-machine materials. These properties limit the use of these materials especially in the commercial markets where cost is much more of a factor than in aerospace. Machining is an important manufacturing process because it is almost always involved if precision is required and is the most cost effective process for small volume production. This paper reviews the machining of titanium and its alloys and proposes potential research issue .