Mechanical Properties of Equal-Channel Angular Extrusion-Processed Al-20Zn Alloy

2012 ◽  
Vol 445 ◽  
pp. 195-200
Author(s):  
Murat Aydin ◽  
Yakup Heyal

The mechanical properties mainly tensile properties, impact toughness and high-cycle fatigue properties, of two-phase Al-20Zn alloy subjected to severe plastic deformation (SPD) via equal-channel angular extrusion (ECAE) using route A up to 2 passes were studied. The ECAE almost completely eliminated as-cast dendritic microstructure including casting defects such as micro porosities. A refined microstructure consisting of elongated micro constituents, α and α+η eutectic phases, formed after ECAE via route A. As a result of this microstructural change, mechanical properties mainly the impact toughness and fatigue performance of the as-cast Al-20Zn alloy increased significantly through the ECAE. The rates of increase in fatigue endurance limit are approximately 74 % after one pass and 89 % after two passes while the increase in impact toughness is 122 %. Also the yield and tensile strengths of the alloy increase with ECAE. However, no considerable change occurred in hardness and percentage elongation of the alloy. It was also observed that the ECAE changed the nature of the fatigue fracture characteristics of the as-cast Al-20Zn alloy.

2013 ◽  
Vol 762 ◽  
pp. 551-555 ◽  
Author(s):  
Marek Stanislaw Węglowski ◽  
Marian Zeman ◽  
Miroslaw Lomozik

In the present study, the investigation of weldability of new ultra-high strength - Weldox 1300 steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on the microstructure and mechanical properties of the heat affected zone (HAZ). In the frame of these investigation the microstructure was studied by the light (LM) and transmission electron microscopies (TEM). It has been shown that the microstructure of the Weldox 1300 steel is composed of tempered martensite, and inside the laths the minor precipitations mainly V(CN) and molybdenum carbide Mo2C were observed. Mechanical properties of parent material were analysed by the tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 - 300 s. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The results show that the impact toughness and hardness decrease with the increase of t8/5 under the condition of a single thermal cycle in simulated HAZ. The continuous cooling transformation diagrams (CCT-W for welding conditions) of Weldox 1300 steel for welding purposes was also elaborated. The steel Weldox 1300 for cooling time in the range of 2,5 - 4 s showed martensite microstructure, for time from 4 s to 60 s mixture of martensite and bainite, and for longer cooling time mixture of ferrite, bainite and martensite. The results indicated that the weldability of Weldox 1300 steel is limited and to avoid the cold cracking the preheating procedure or medium net linear heat input should be used.


2010 ◽  
Author(s):  
K. J. Kim ◽  
D. Y. Yang ◽  
J. W. Yoon ◽  
F. Barlat ◽  
Y. H. Moon ◽  
...  

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 978 ◽  
Author(s):  
Pengfei Wang ◽  
Zhaodong Li ◽  
Guobiao Lin ◽  
Shitong Zhou ◽  
Caifu Yang ◽  
...  

Steels used for high-speed train wheels require a combination of high strength, toughness, and wear resistance. In 0.54% C-0.9% Si wheel steel, the addition of 0.075 or 0.12 wt % V can refine grains and increase the ferrite content and toughness, although the influence on the microstructure and toughness is complex and poorly understood. We investigated the effect of 0.03, 0.12, and 0.23 wt % V on the microstructure and mechanical properties of medium-carbon steels (0.54% C-0.9% Si) for train wheels. As the V content increased, the precipitation strengthening increased, whereas the grain refinement initially increased, and then it remained unchanged. The increase in strength and hardness was mainly due to V(C,N) precipitation strengthening. Increasing the V content to 0.12 wt % refined the austenite grain size and pearlite block size, and increased the density of high-angle ferrite boundaries and ferrite volume fraction. The grain refinement improved the impact toughness. However, the impact toughness then reduced as the V content was increased to 0.23 wt %, because grain refinement did not further increase, whereas precipitation strengthening and ferrite hardening occurred.


Author(s):  
Temitayo Mufutau Azeez ◽  
Lateef Owolabi Mudashiru ◽  
Tesleem Babatunde Asafa ◽  
Adekunle Akanni Adeleke ◽  
Adeyinka Sikiru Yusuff ◽  
...  

Author(s):  
T.M. Azeez ◽  
Lateef O. Mudashiru ◽  
T.B. Asafa ◽  
A.A. Adeleke ◽  
Peter Pelumi Ikubanni

Mechanical properties of extruded aluminum are known to significantly depend on the process parameters such as temperature, numbers of extrusion pass and extrusion load among others. This implies that these properties can be influenced by tuning the process parameters. Herein, the effects of these parameters on the tensile strength and hardness of aluminum 6063 series were investigated by using equal channel angular extrusion (ECAE). Experiments were designed using Design Expert software. Analysis of variance (ANOVA) was then used to investigate the main and interactions effects of the process parameters. An empirical mathematical model was generated that shows the relationship between the input and output variables using response surface methodology. Temperature was found to be the most significant factor while extrusion load was the least factor that influenced the hardness and tensile strength which were the output factors. There was a significant increase in tensile strength and hardness after extrusion at different mix of factors. The optimum input variable was discovered at 1020.58 kN, 489.67°C and 3 numbers of extrusion passes.


Author(s):  
S Mohan Kumar ◽  
R Sasikumar ◽  
A Rajesh Kannan ◽  
R Pramod ◽  
N Pravin Kumar ◽  
...  

Wire plus arc additive manufacturing (WAAM) technology with higher deposition rate and efficient material utilization was employed to fabricate a stainless steel 321 (SS 321) wall for the first time. In this work, the microstructural characteristics, mechanical properties and corrosion performance of as-built SS 321 were evaluated. The micrographs confirmed the presence of columnar and equiaxed dendrites along the building direction, and recrystallization of grains was noticed due to the re-melting of former layers. The microstructure was dominantly austenite with a small fraction of ferrite within the austenitic matrix. Better tensile properties were noticed for as-printed SS 321 WAAM samples in-comparison to wrought counterpart. This is corroborated to the equiaxed and columnar dendritic microstructure with small fraction of ferrite (FN). The hardness decreased from bottom (247 HV) to top (196 HV) region in SS 321 WAAM plate and is attributed to the microstructural difference with varying amount of ferrite (6.3 to 3.7 FN). The impact strength of samples in the horizontal and vertical direction was 116  ±  2 J and 114  ±  2.5 J respectively, and is comparable with the wrought AISI 321 (123  ±  1.5 J). The reduction in impact toughness is attributed to the ferrite (<6.3 FN) fraction. Polarization curves and Nyquist plots elucidate the excellent pitting resistance of SS 321 WAAM specimens, and the corrosion rate was less than 1 mils per year (mpy). Corrosion cracks were absent, and the passive film formation in the WAAM specimens were compact and highly stable for corrosive environments.


Sign in / Sign up

Export Citation Format

Share Document