Cu-Based Shape Memory Alloys: Modified Structures and Their Related Properties

Cu-Al-Ni shape memory alloys (SMAs) have been developed for high-temperature applications due to their ability to return to pre-deformed shape after heating above the transformation temperature, as well as these alloys have a small hysteresis and high transformation temperature comparing with other shape memory alloys. Adding some of the alloying elements such as Ti, Mn, Be, Zr and B or changing the interior content either Al or Ni by increasing/decreasing may have a significant effect on the phase transitions and enhance the mechanical properties of these alloys. However, the martensite phase transformation is the most important factor, which can be changing the whole properties of Cu-Al-Ni SMAs, where this phase is mainly affected by the alloying elements additions. This chapter reviews the effect of alloying elements on the phase transitions and the enhancement of the mechanical properties of this alloy

Influence of alloying elements and aging treatment on the phase transformation and shape memory behavior of Cu-Al-Ni shape memory alloys

Nickel-Titanium (Ni-Ti) shape memory alloys (SMAs) have been used in many engineering and medical applications. However, their use is limited, due to their low transformation temperatures, difficulties in processing and high cost of the raw materials. As an alternative material to Ni-Ti alloys, copper-based alloys are successfully being used. Among copper-based SMAs, Cu-Al-Ni alloys are used in a wide range of applications, particularly if high temperatures are required. However, Cu-Al-Ni SMAs also have limitations such as very low ductility and low shape recovery strain. Therefore, this research aims to enhance the ductility and shape memory effect of Cu-Ni-Al by alloying additions and aging heat treatment. The base metal, Cu-Al-Ni, was cast without and with different amounts of the fourth alloying elements, namely, titanium (Ti), manganese (Mn) and cobalt (Co). The modified and unmodified alloys were homogenized and aged at 373 K, 423 K and 523 K for 24 and 48 hours. Phase transformation and microstructural changes were characterized using techniques such as optical microscopy, field emission scanning electron microscopy (FESEM), energy dispersive spectrometry (EDS), differential scanning calorimetry (DSC), x-ray diffractometry (XRD) and transmission electron microscopy (TEM). The tensile properties and hardness were determined using a universal Instron tensile machine and Vicker‟s hardness test machine, respectively. The shape memory test was performed using a specially designed tensile machine equipped with a heating tape. The results revealed that the alloying elements and aging treatment were found to control the phase morphology, orientations and grain size along with the formation of precipitates, thereby improving the shape memory characteristics, ductility and hardness. The volume fraction, size and distribution of the precipitates are mainly dependent on the type and amount of alloying element as well as the condition of aging treatment. The Cu-Al-Ni with the addition of 0.76 wt. % Ti and age treated showed complete recovery after the shape memory test. This may be attributed to the high volume of X-phase precipitates and grain refinement that led to the restricted mobility of martensite variant interfaces and dislocations. It was found that the alloy with 1.14 wt. % of Co gave the best overall improvement in terms of the transformation temperatures, ductility and shape memory recovery. These improvements were mainly due to the exceptionally high content of the gamma-2 (γ2) phase in the microstructures of the modified alloy. Furthermore, the ductility of the Cu-Al-Ni SMAs increased from 1.65 to 7.0 % when 1.14 wt. % Co was added and the alloy undergone aging treatment where the fracture surfaces showed more ductile features and less brittle cleavages. It was also found that Cu-Al-Ni SMAs with 1.14 wt. % Co obtained full shape recovery after being aged at 523 K for 48 hours

Phase transformation and microstructure behaviour of Cu-Al-Ni shape memory alloys incorporated with cobalt addition

The effect of Co addition on phase transformation temperatures and microstructures of Cu-Al-Ni SMA were investigated via differential scanning calorimetry, field emission scanning electron microscopy corresponding with energy dispersive spectroscopy and x-ray diffraction. The results revealed that the β1’ and γ1’ phases’ morphology and orientation were varied after the addition of Co along with the presence of intermetallic compounds known as γ2. This phase was indicated using the EDS and XRD is related to the intermetallic compound of Al75Co22Ni3. In addition, the phase transformation temperatures tend to increase with the addition of Co and this enhancement is mainly attributed to the variation of phase morphology and the existence of γ2 precipitates

Microplastics in marine benthic filter feeder: A review on the occurrence, routes of ingestion, method of extraction and effects to the ecosystem

Plastic pollution has been a global concern as it contaminates the earth. Hence, the purpose of this review discusses the rate of plastic pollution and how it has accumulated in the various benthic feeders in the ocean. This review focuses on the occurrences of microplastics, routes of ingestion, method of extraction and the effects of plastic on marine ecosystems. The marine invertebrates considered in this study include filter and benthic feeders. Hence, a compilation of 54 published studies, reviewed articles, conference materials and books from related topics were reviewed to identify the gaps in the research. Microplastics were identified with a scheme to colour, size, shape and polymer type. Techniques to extract these microplastics were also described. Findings from this review showed that the animals tended to accumulate large amounts of denser forms of microplastics. Therefore, this review will be a fundamental touchstone for the studies regarding microplastics in marine invertebrates

Development of an internet of things-based weather station device embedded with O2, CO2, and CO sensor readings

Weather station devices are used to monitor weather parameter conditions, such as wind direction, speed, rainfall, solar radiation level, temperature, and humidity. This article discusses the design of a customized weather station embedded with gas concentration readings, whereby the gas concentration measurement includes oxygen (O2), carbon dioxide (CO2), and carbon monoxide (CO). The measurements and data processing of input sensors were transmitted to an Arduino Uno microcontroller, and the input data were then remitted to Wemos D1 Mini to be uploaded to a cloud server. Furthermore, the gas sensors' characterization methods were also considered to reveal the obtained results of accuracy, precision, linearity, and hysteresis. An android-based mobile application was also designed for monitoring purposes. The system in our experiment utilized an internet connection with a field station, base station, and database server

Microplastics Isolated from Saltwater Clam Paratapes undulatus from Wet Market at Shah Alam, Selangor, Malaysia

Plastic waste has become a serious environmental threat because of large scale demand and poor disposal methods. Microplastics, defined defined as plastic waste with a diameter spanning from 5 mm to 1 μm, may easily enter the ocean and cumulatively ingested by marine life, which will eventually be consumed by humans. The goal of this study is to determine the types of microplastic that can be found in the saltwater clam Paratapes undulatus collected in Kuala Selangor, a fishery hub in Peninsular Malaysia. A total of 30 P. undulatus samples were collected and the soft tissue inside was dissected and digested using NaOH. The digestates were then vacuum-filtered to obtain the microplastics. Microplastics were identified based on their physical characteristics under microscopic examination (colour, shape and size). Fourier Transform Infrared Spectroscopy (FTIR) was used to determine the polymers based on the functional group of the plastics’ molecular structure. A total of 2,072 microplastic particles were isolated from all clam samples. In terms of colour and shape, the majority of microplastics were black (64.48 %) and in the form of fibres (97.2 %). Most of the microplastic particles had sizes ranging from 0.5 to 1 µm and 1 to 2 µm. Polystyrene (PS) and polymethyl methacrylate (PMMA) were two common polymers. This study indicates that clams harvested off the coast Kuala Selangor may be contaminated with microplastics from their habitat. More research is needed to assess the toxicity and potential threat of microplastics to human health when consuming seafood

Modeling the Physical Properties of Gamma Alumina Catalyst Carrier Based on an Artificial Neural Network

Porous γ-alumina is widely used as a catalyst carrier due to its chemical properties. These properties are strongly correlated with the physical properties of the material, such as porosity, density, shrinkage, and surface area. This study presents a technique that is less time consuming than other techniques to predict the values of the above-mentioned physical properties of porous γ-alumina via an artificial neural network (ANN) numerical model. The experimental data that was implemented was determined based on 30 samples that varied in terms of sintering temperature, yeast concentration, and socking time. Of the 30 experimental samples, 25 samples were used for training purposes, while the other five samples were used for the execution of the experimental procedure. The results showed that the prediction and experimental data were in good agreement, and it was concluded that the proposed model is proficient at providing high accuracy estimation data derived from any complex analytical equation

Effectiveness of an instructional program on attitudes of parents toward children with attention deficit hyperactivity disorder in autism centers at Baghdad City

Objective: To find out the effectiveness of instructional program on attitudes of parents toward children with Attention Deficit Hyperactivity Disorder.  Methodology: A quasi-experimental study was conducted that included (120) deliberate samples of parents selected from eight autism centers according to the study criteria (60) parents in the centers (Al-Safa, Al-Marwa, Basmat Amal, Al-Tahadi), and (60) parents in the centers (Al-Rami, Al-Rahman, Al-Takhassusi, Al-Saeeda Family. The samples were divided into two groups (60) parents (study group) who participated in the instructional program and (60) parents (control group) who did not participate in the program. The groups are almost identical in their properties. The instructional program was implemented in four steps, the first step (pre-test) is to assess parents' attitudes towards children with ADHD before implementing the program, and the second step is to implement the program and then two tests and the time period between the first and second test is two weeks. The validity and reliability of the questionnaire were determined by a group of experts and through a pilot study of ten parents. Descriptive and inferential statistics were used to analyze the data. &nbsp