Aluminium Metal Matrix Composites: Literature Review

Aluminium Metal Matrix Composites: Literature Review Literature Survey- Based on Aluminium Metal Matrix Composites. 1]Shilpa P.S et al They studied the effect of reinforcement of Boron Carbide with the Al2024. By adopting stir casting technique fabricated the specimen by varying the wt% of Boron Carbide. The specimens are developed as per the ASTM. In the end they come to know that as the reinforcement Boron Carbide increased by wt% increases the Hardness, Tensile strength and Yield strength. The percentage of elongation decreases with the increase of Boron Carbide in the composition. 2]F.Abdi et al-They investigated the effect of 5 wt% of TiB2 as a reinforcement with the Al356.1 metal matrix at various temperature i.e.750c, 850c, 950c using stir casting technique. They found that at temperature 950c shows best result s for Tensile strength and Hardness and the TiB2 particles are homogenously distributed. 3]Sandeep Kumar Ravesh et al(C)-They investigated the effect of the various weight fraction of SiC i.e.2.5%,5%,7.5% and 10% and 5% flyash is reinforced with Aluminium 6061 metal matrix composite by using the stir casting method. They observed that Tensile strength, Harness and Impact strength increased with the increase in weight fraction of SiC particle. A best tensile strength 115 N/mm2, hardness 93RHN and toughness value 7.8 for 10% SiC and 5% flyash reinforced composite material was obtained. 4]K.L.Meena et al(D)-They investigated the mechanical properties of the   developed SiC reinforced with Al6063 metal matrix composite material using Melt stirring technique where the experiment was carried out by varying the reinforcement particle size such as 200 mesh, 300 mesh, 400 mesh with the different weight percentage i.e..5%, 10%, 15% and 20% of SiC particle reinforced material. The stirring process was carried out at the speed of 200rpm using the graphite impeller for a period of 15min. A homogenous dispersion of SiC particle in the aluminium matrix was observed. The tensile strength, hardness and yield strength were improved with the enlargement of particulate size and weight percentage of SiC. Percentage reduction area and percentage elongation and impact strength decreases as the increase in reinforced particle size and weight percentage of SiC particle. Maximum hardness (HRB) 83 and impact strength 37.01 Nm was achieved. 5]H.G.Rana et al-They investigated the mechanical properties and wear properties of Al7075 with the reinforcement of Boron Carbide. They concluded that using the using Friction Stir casting the fabricated specimens provides uniform mixing and enhances the tensile strength and hardness. Hence the microstructure are studied with the help of Image analyser. Based on Zirconia as Reinforcement. 6]Ram Narayan et al They investigated the effect of flyash and zirconia with the mechanical properties of Aluminium 6061 alloy composite samples developed by using the technique Stir casting. They developed the specimen by varying the zirconia (5% and 10%) and kept the flyash 10% as a fixed percentage by weight fraction. They observed that due to the presence of flyash and zirconia Hardness and Tensile strength was increased where the elongation decreased as compared to the unreinforced aluminium. The characterization will be done using the scanning the electron microscope machine and image analyser. 7]S. Roseline et al They observed the mechanical properties of aluminium alloy mmc with the reinforcement of fused Zirconia alumina. They developed the specimens by varying by the weight fraction by percentage. They evaluated the mechanical properties which indicates the variations in the Hardness, Tensile strength and Impact strength. The optimum result for mechanical properties found on the reinforcement to be 90 and 10 by weight percentage of the matrix respectively. 8]Jithin Jose et al-They investigated the effect of flyash and zircon (zirconium silicate) with the mechanical properties of Aluminium 7075 alloy and the stir casting technique was adopted to develop the specimens by varying weight percentage .They after conducting the different test concluded that keeping the zircon at a fixed weight percentage and varying the flyash found that the wear rate decreases where the tensile strength and the hardness increases. 9]Adil Ahmed.S et al-They studied the incorporation of Zirconium Nano Particles in Al356.2.The stir casting technique was used for the development of composite specimen where the Al356.2 is heated at around 750c and the Zirconium Nano particles are added .Mechanical properties are increased for 15wt% of reinforcement particle developed at 750c shows homogenous reinforcement particle and through using the Scanning Electron Microscope the microstructure of the specimen shows homogenous reinforcement. 10]J.Jenix Rino et al-They investigated the mechanical properties of Aluminium 6063 alloy composite enhance i.e. strengthened by the addition of alumina particle and zircon sand with an overall reinforcement in the Al6063 material matrix. They observed the Hardness and Tensile strength of the composite having higher value at the composite developed specimen, which having reinforcement mixture of 4wt%ZrSiO4+4wt% Al2O3. 11]K.B. Girisha et al-They studied the effect of various weight fraction of zirconium oxide nanoparticle i.e. 0.5%,1%,1.5% and 2% reinforced with Al356.1 metal matrix composite by using stir casting technique. Here they observed that particle agglomeration in the composite is due to high amount of zirconium oxide nanoparticle. Hardness and wear properties are increased as the increase in weight fraction of zirconium dioxide nanoparticle. 12]M.A.Baghchesara et al They studied the mechanical properties of developed composite specimen using the stir casting method where they considered zircon and TiB2 ceramic particles with size 1 micron and the temperature 750c respectively. The microstructure were studied by using scanning electron microscopy and hence the dispersion of reinforcement as noted. Situation of compounds of the developed specimen were examined by XRD. The end results shows mechanical properties and microstructure behavior of composite was improved compared to the monolithic alloy. Microstructures of the composites in as cast conditions shows uniform distribution of the particles and reveals the better bending in case of zircon reinforced composites compared to the TiB2 composites. But increase in the amount of reinforcement shows better conditions in case of TiB2 reinforced composites. Based On Flyash with Aluminium- 13] H.C. Anilkumar et al-They investigated the mechanical properties of Al 6061 reinforced by flyash. They fabricated the composite specimens using the stir casting method. They developed three sets of composites with particle size of flyash of 4-25,45-50 and 75-100 µm was used. The three set of composites are developed by varying weight fraction of 10%, 15% and 20%. The mechanical properties are like Tensile strength, Compressive strength, hardness and Ductility are studied. They found that increase of particle size of flyash decreases tensile strength, compressive strength and hardness of the developed specimens. They also find that by increase of weight fraction of flyash increases compressive strength ultimate tensile strength, hardness but decreases with increase of flyash particle size. 14]Muruganandhan.P et al-They investigated the effect of flyash reinforced with Al6061.By varying the wt% of flyash using the stir casting method the specimens was developed. The found that increase of flyash increase the mechanical properties upto 20% of fly ash in the metal matrix but the corrosion resistance decreases with increase of flyash addition. 15] M.Sankar-They investigated the Silicon carbide and Flyash reinforced with the Aluminium 6061 alloy.They developed the specimens using the stir casting method.They found that as the reinforcement contents increased in the matrix material, the composites hardness also increased. Tensile strength decreased with increased amount of reinforcement.   The wear rate of the composites reduced with increased weight percentages of the reinforcements. Who was Responsible for the Cold War? Who was Responsible for the Cold War? When looking at the issue of who was responsible for the cold war, we have to look at what the relationship between the United States and USSR (Union of Soviet Socialist Republics) was like before the start of World War Two. By the end of the nineteenth century Marxism in Western Europe was becoming more and more national. The imperial implications of both Marxist thought and Russian history provide the broad background and context for understanding soviet involvement in cold war. The soviet worldwide had been shaped by a history that was dramatically different from that of the west  [1]  . For example the Bolshevik revolution, the civil war, and the experience of World War two all contributed to a unique soviet perspective. Furthermore after the revolution of 1917, soviet Russia assumed the responsibility of spreading the Marxist message. Stalin seen himself as the keeper of the Marxist faith, it would emancipate mankind  [2]  . In addition historians such as Zubok and Const antine suggest that history gave the Russians the reason to see themselves as saviours of the world. Due to the events that occurred before the Cold War we can see this. Furthermore historians believed that each of them would make his own intricate cold war journey, guided by the two misleading suns of empire and revolution. Many historians believe that it was because, the United States and USSR ideologies were so different and believed that to be the underlying cause for their fear of one another. For example Russia was communist which put the needs of the state ahead of personal human rights and was ruled by a dictator. The USA was a capitalist democracy which valued freedom and believed that communism was something to fear. Americans saw themselves as champions of the free world, and tyrants such as Stalin represented everything the United States opposed. At the same time, the Soviets, who believed that capitalism exploited the masses, saw the United States as the oppressor. To emphasise the difference between the two nations we can see this by looking at their visions of the world. For example Stalin saw the world as divided into two camps: imperialist and capitalist regimes on the one hand, and the Communist and progressive world on the other. In 1947, President Harry Truman also spoke of two diamet rically opposed systems: one free and the other bent on subjugating other nations. Although World War Two was meant to be the War to end all wars it was not, the repercussions and the aftermath of what the war had caused, it just lead to a more apprehensive atmosphere all over the world, and as we can see this was defiantly the case when considering the relationship between the US and USSR. Although relations went on a downward spiral after World War Two it was not always this way, they were once allies during World War Two. However things changed after WW2, once the threat of Hitler was over, they became fearful of each other, Russias hatred for capitalism deepened when they was not rewarded for their efforts during World War Two, instead they became focused back on by the world that they was the threat the red scare began to intensify. Moreover historians have suggested that because of the enormous sacrifice of the Russian people in the Second World War, had led to the soviet lea ders to believe that the allies owed them a great deal. The cold war emerged from the ruins of world war two  [3]  Stalin expected to be rewarded for their contribution in the war especially when Russia lost 27 million people. His primary task was to regain the territories lost to Russia during the war and revolution from 1915 to 1921: the Baltics, Finland, Poland, and Bessarabia. This goal was virtually fulfilled by the end of 1945. The Cold War was a period of East-West competition, tension, and conflict short of full-scale war. It was characterized by mutual perceptions of hostile intention between military-political alliances or blocs, both systems believed that they were doing the right thing. The events that happened before and after World War two had an irreversible impact on how both of these countries perceived one another. Furthermore Stalins foreign policies contributed an enormous amount to the tensions of the Cold War. His aim, was to take advantage of the military situation in post-war Europe to strengthen Russian influence, this was perceived to be a threat to the US and everything they stood for. Stalin was highly effective in his goal to gain territory, with victories for example in Poland and Romania. To the western world, this success looked as if it were the beginning of a series of Russian aggressions. The aggressive expansion in Eastern Europe was one of the main reasons for the cause of the cold war. Therefore it can be questioned that if the Soviets had not adopted the expansionist policy, then the Truman Doctrine and the Marshall Plan may not have been initiated to keep Stalin and his spread of communism at bay. Furthermore Stalins own persona could be seen as another cause for the cold war, for example when Ivan Maisky and Maxim Litvinov were appointed in 1943. Maisky wrote that the main soviet goal after the war would be to ensure a durable peace enough for the USSR to become so powerful that no combination of powers in Europe or in Asia could even think of threatening her  [4]  . This suggest that even though Russia had not got the rewards they was expecting from World War two and the contribution of the west in the civil war in 1918 all contributed to Stalins view on spreading Communism and being strong enough to not be threatened or have a fear of being invaded by any other country. In addition Stalins actions to wanting to spread communism throughout the world, lead to policies such as the china policy which historian Odd Arne Westad came to the conclusion that Joseph Stalin china policy in the fall of 1945 was as aimless and incoherent as his European policy. However much he hoped to avoid post war confrontation with the United States, Stalin could not make his mind how to achieve this aim.  [5]  This view gives important insight into the impact of Stalins persona on the origins of the cold war. In addition Historians have also wondered whether another cause for the cold war was Stalins poor diplomacy. For example the diplomatic pressure he put on turkey caused him great problems with the west and later in 1948 his attempt his attempt to remove Tito in Yugoslavia by means of communist democracy backfired and only weakened their position. The errors Stalin made and the policies he created showed him to be aggressive and wanting to expand USSRS borders spreading they way of communism. This ultimately created more of a hysteria and fear in US, therefore being a main contributor to the cause of the Cold War. In addition when the Western democracies and the Soviet Union met up to discuss World War II, and the nature of the post-war settlement at conferences in Tehran 1943, Yalta February 1945, and Potsdam July-August 1945. At these conferences the Soviets agreed to allow the nations of Eastern Europe to choose their own governments in free elections. Stalin agreed to the condition only because he believed that these newly liberated nations would see the Soviet Union as their savoir and create their own Communist governments. When they failed to do so, Stalin violated the agreement by wiping out all opposition to communism in these nations and setting up his own governments in Eastern Europe, causing the situation to intensify. To make the situation worse, Stalin deepened the estrangement between the United States and the Soviet Union when he asserted in 1946 that World War II was an unavoidable and inevitable consequence of capitalist imperialism and implied that such a war might reoccur. This resulted in an increase in world spread fear of communism due to Stain basically going towards the thought of another World war, which could have lead to a nuclear war. In addition many of the tensions that existed in the Cold War can be attributed to Stalins policy of Soviet expansion. It is necessary to consider that the role of Stalin can be seen as a catalyst to the Cold War Furthermore the situation involving Poland was that Poland had always been the key state needed from which to launch an attack against Russia. He also wanted Poland to have a pro-Soviet government. Therefore after some time, he set up a communist government in Poland. He said that his control of Eastern Europe was a defensive measure against possible future attacks to the west it appeared to them that Russias attitude went against all of the promises that Stalin had made at Yalta mainly that Stalin would permit free elections in the eastern European states. Russia argued that it needed to maintain a sphere of influence in the area for security reasons. This caused further anxiety over Stalins policy of expansion. This then lead to the West to introduce the Truman Doctrine and the Marshall Plan, both of which sought to arrest the spread of communism. The initiation of the Marshall plan for European recovery, however from Stalins point of view the marshal plan was a large scale attempt by the United States to gain lasting influence in Europe. The marshell plan was a serious challenge to Stalin vision of a future Europe as well as to German- soviet relations. Thus he had to protect his borders but by doing so it caused him to look like an aggressive bully towards countries that would not follow his lead. For example when leadership of Czechoslovakia hesitated before ending their participation in the Marshall plan it outraged Stalin, he told Czechoslovakia immediately to cancel the plans to receive aid from the US, Gottwald (leader of Czechoslovakia) complied. This just shows the intimidation Stalin was willing to put other nations through to keep them communist and not wade to the side of the US. The nations that complied with Stalin and agreed not to participate in the Marshall plan, their economies deteriorated, while those of th e western European states began to recover and see improvement in their economies. To Stalin this was a challenge of his authority in Eastern Europe, therefore his next actions was to focus on Czechoslovakia, the communist group in Prague carried out a coup in February of 1948. Shortly after the coup the Czech president was replaced by the leader of the Czech communist party, Gottwald. Furthermore it was incidents like these that caused outrage in the western world, the intimidation of another country to not take a chance that could help their economy, to stop them countries from distracting from the way of communism rather than capitalism. Thus if Russia had not behaved and acted this way due to their expansion policy , it may not have ever got out of control and there would have been no need to implement the Marshall plan which lead to the implementation of the Truman Doctrine. To further Americas fear of communism, due to their aggressive foreign policy, between 1943-46 most western European Communist parties were at a peak in the years immediately following World War Two. The French Communist Party, for example, won almost 30% of the vote in 1946 elections. Greece was in crisis they were at the brink of civil war which finally occurred in 1946 after the Greek communists tried to seize power in 1944 due to a rise in communist leg guerrillas. This resulted in an economic crisis which at the time was being supported by Britain however this was no longer possible. Therefore America stepped in because they feared that the people would look more towards communism through desperation. This then resulted in the introduction of the Truman Doctrine in March, 1947. The Truman doctrine announced that was to be given to Greece and Turkey in the stated context of a general war against communism. The US gives $400 million as aid to help Greece in their economic crisis. However it can be said that in many ways, the Truman Doctrine marked the formal declaration of the cold war between the United States and the Soviet Union .It also solidified the United States position regarding containment. However, even though this suggests that US started the war, but if Russia had not been aggressively expanding their empire and spreading communism then it would not have caused the US to intervene and introduce the Truman doctrine due to their fear of communism. By 1946, the United States and Britain were making every effort to unify all of Germany under western rule. The Soviet Union responded by consolidating its grip on Europe by creating satellite states in 1946 and 1947. One by one, communist governments, loyal to Moscow, were set up in Poland, Hungary, Romania, and Bulgaria. Stalin used Soviet communism to dominate half of Europe. This created more of a mistrust in the USSR and the US relations resulting in the build up to the Cold War, and evidently showing that the roots of the problem was the Russias expansion policy. In relation to the previous point made to show Russias expansion during the time leading up to the Cold war, we have to look at Winston Churchill Iron Curtain. Churchill said that From Stettin on the Baltic to Trieste on the Adriatic, an iron curtain has descended across the continent. Behind that line lie all the capitals of the ancient states of central and Eastern Europe -Warsaw, Berlin, Prague, Vienna, Budapest, Belgrade, Bucharest and Sofia.  [6]  Therefore showing the scale of how fast Russia was expanding through Eastern Europe. It also emphasis the split between Russia and the US creating more of an estranged relationship between the two super powers, because it is showing the spread of communism and how quick it was occurring. The United States feared the most was the Red Scare which was becoming more serious with each invasion of the countries within Eastern Europe. Stalin also set up the Berlin Blockade with the idea that he could push western power out of Eastern Berlin, which only escalated the situation. The cold War was the brave and essential response of free men to Communist aggression.  [7]  Schlesinger believes that the soviets were wrong and that the USA was trying to stop the USSR from going any further. Another view is T.A. Bailey who also believed that the Soviets were to blame; he thinks that they always had one more plan for world domination up their sleeves. In addition further actions took by Stalin which was contributing to the end result in being the cold war, was the Berlin Blockade on the 24th June 1948. Stalin decided to blockade West Berlin by cutting off road and rail links. To break the blockade armed forces would have to smash the blockade, however this would be seen as an act of war which Stalin new US wouldnt do. He believed they would abandon their zones and leave the whole of Berlin in soviet hands. However Stalin failed to gain control of Berlin. Although he failed in this case, it still antagonised America causing them to retaliate. Therefore due to Stalin wanting to gain a foot hold in Europe and to keep aggressively expanding. This shows that each action Stalin made were all catalysts in causing the Cold War. In addition the relationship between Russia and the US escalated further to the extent were another proxy war was occurring, which was the Korean War (1950- 1953). The Korean War was a military conflict between the Republic of Korea, supported by the United Nations, and the Democratic Peoples Republic of Korea and Peoples Republic of China (PRC), with air support from the Soviet Union. The war began on 25 June 1950 it was a result of the political division of Korea by agreement of the victorious Allies at the conclusion of the Pacific War. In 1945, following the surrender of Japan, American administrators divided the peninsula along the 38th Parallel, with United States troops, occupying the southern part and Soviet troops occupying the northern part. It was soviets foreign policy that lead to them being involved in the Korean War however it was China who physically participated in the war, where as Russia was acting behind the scenes to not actually cause a physical war between them and the US. By being involved in the war it just caused the US to be more wary of Russia and showed how much influence and power the USSR had gained to have that control over China and other countries that were also communist. After looking at the events leading up to the cold war, the short term and long term causes when focusing on the US perspective we see that their view was flawed because they feared what they did not understand, they did not understand how a country could be ran under a communist government and still work, especially when the US system was capitalist. The USs response was based on their misunderstanding and fear of USSR which was more commonly known as the red scare. For example the US and Britain believed that just before WW2 they seen the USSR as more of a threat than Hitler at that time. Overall some historians such as the Traditionalist believed that Russia was to blame for the Cold War. They believed that the Soviet-led governments sought to overthrow existing capitalist governments, which can be reinforced by the fact that Russias foreign policy was aggressive expansion. In addition the US and its allies were merely responding to the threats of the Soviet Union, as we can see by the Truman doctrine. I agree with traditionalists idea due to the fact that Stalin and his successors were convinced that the legitimacy of their rule depended on validating Marxist-Leninist predictions of world revolution. If they believed that they would only succeed when these predictions were completed then they were to blame for the cold war. Russia actions of aggressive expansion throughout Eastern Europe support this.