液相燒結(jié)90W-7Ni-3Fe高密度鎢合金組織性能研究
發(fā)布時(shí)間：2018-11-21 12:04
【摘要】：高密度鎢合金是一種典型的兩相合金,具有高密度、高強(qiáng)度和良好的塑性等優(yōu)異性能,是制作動能穿甲彈彈芯的主要材料。穿甲彈從發(fā)射、飛行到穿甲侵徹的過程中處在溫度場和應(yīng)力-應(yīng)變場耦合環(huán)境下,所以綜合研究鎢合金在溫度場和應(yīng)力-應(yīng)變場下的變形和失效行為是非常必要的。本課題選用液相燒結(jié)90W-7Ni-3Fe高密度鎢合金作為實(shí)驗(yàn)材料,重點(diǎn)研究了鎢合金在室溫、高溫不同應(yīng)變速率下的拉伸和壓縮力學(xué)性能,并對鎢合金在室溫下的動態(tài)力學(xué)性能和微觀組織也進(jìn)行了實(shí)驗(yàn)分析,同時(shí)建立了基于不同模型的本構(gòu)方程。本文對燒結(jié)態(tài)90W合金的基本物理及力學(xué)參數(shù)進(jìn)行了測定和表征,對90W在室溫下的力學(xué)性能和微觀組織進(jìn)行實(shí)驗(yàn)分析。發(fā)現(xiàn)90W合金在室溫拉伸時(shí)隨著應(yīng)變速率增加,強(qiáng)度增加、塑性降低、W顆粒的解理斷裂增加、粘結(jié)相的韌性撕裂減少;在室溫壓縮時(shí),塑性變形是鎢相與粘結(jié)相變形相互協(xié)調(diào)的過程,在應(yīng)變速率10-3s-1塑性最高;90W合金在動態(tài)壓縮時(shí)相對于準(zhǔn)靜態(tài)壓縮屈服強(qiáng)度明顯升高。90W合金在473-1473K高溫拉伸實(shí)驗(yàn)結(jié)果表明應(yīng)變速率對高溫力學(xué)性能影響并不顯著。研究發(fā)現(xiàn)90W合金在673K和1273K時(shí)強(qiáng)度和塑性出現(xiàn)明顯變化,強(qiáng)度在473-673K時(shí)明顯降低,隨后升高并出現(xiàn)平穩(wěn)臺階直到1273K時(shí)再次出現(xiàn)明顯下降;塑性在673K最高,隨溫度升高緩慢降低在1273K時(shí)已經(jīng)基本沒有塑性并趨于穩(wěn)定。通過對斷口的掃描發(fā)現(xiàn),在673K時(shí),90W的斷裂方式以粘結(jié)相的韌性撕裂為主,極少看到W-W沿晶斷裂。對90W合金在1073至1473K、應(yīng)變速率10-3s-1至10-1s-1下壓縮實(shí)驗(yàn)表明,90W合金力學(xué)行為受溫度和應(yīng)變速率耦合影響,在1473K、應(yīng)變速率10-3s-1時(shí)力學(xué)性能明顯惡化,試樣中心部位出現(xiàn)鎢顆粒異常長大現(xiàn)象;在1073K壓縮時(shí),試樣邊角部位出現(xiàn)于壓縮方向成45°的剪切帶,溫度上升到1473K,邊角部位相界面則由于變形不一致導(dǎo)致相界面產(chǎn)生大量缺陷。為了描述90W合金在高溫下的塑性變形行為,本文建立了基于JC模型、修正后JC的模型、Arrhenius模型和修正后的ZA模型等四個(gè)模型共六個(gè)本構(gòu)方程,其中針對JC和修正后的JC分別以293K和1073K為基準(zhǔn)建立了本構(gòu)方程。對每個(gè)方程的準(zhǔn)確性和預(yù)測性利用相關(guān)系數(shù)和平均相對誤差來進(jìn)行定量計(jì)算。通過對比可以得出,以Arrhenius模型和修正后的ZA為基礎(chǔ)所構(gòu)建的本構(gòu)方程有較高的準(zhǔn)確度和擬合度,以JC和修正后的JC模型建立的本構(gòu)方程誤差較大,這是因?yàn)锳rrhenius模型和ZA模型比較全面的考慮了溫度、應(yīng)變和應(yīng)變速率對應(yīng)力的耦合效應(yīng)。
[Abstract]:High density tungsten alloy is a typical two-phase alloy with excellent properties such as high density, high strength and good plasticity. The armor-piercing projectile is in the coupled environment of temperature field and stress-strain field during the process of launching, flying and penetrating through the armour. Therefore, it is necessary to study the deformation and failure behavior of tungsten alloy under the temperature field and stress-strain field. In this paper, 90W-7Ni-3Fe high density tungsten alloy sintered in liquid phase was selected as the experimental material. The tensile and compression mechanical properties of tungsten alloy at different strain rates at room temperature and high temperature were studied. The dynamic mechanical properties and microstructure of tungsten alloy at room temperature were also analyzed experimentally, and constitutive equations based on different models were established. The basic physical and mechanical parameters of sintered 90W alloy were measured and characterized. The mechanical properties and microstructure of 90W alloy at room temperature were analyzed experimentally. It is found that the tensile strength of 90W alloy decreases with the increase of strain rate at room temperature, the cleavage fracture of W particles increases and the ductile tear of bonding phase decreases. At room temperature compression, plastic deformation is the process of coordination between tungsten phase and bonding phase deformation, and the plasticity is the highest at strain rate 10-3s-1. Under dynamic compression, the yield strength of 90W alloy is obviously higher than that of quasi-static compression. The tensile test results at 473-1473K show that the strain rate has no significant effect on the mechanical properties at high temperature. It was found that the strength and plasticity of 90W alloy changed obviously at 673K and 1273K, the strength decreased obviously at 473-673K, and then increased and stable steps appeared until 1273K. The plasticity is the highest at 673K, and decreases slowly at 1273K with the increase of temperature. By scanning the fracture surface, it is found that at 673K, the fracture mode of 90W is mainly the ductile tear of the bonding phase, and the W-W intergranular fracture is rarely seen. The compression tests of 90W alloy at 1073 ~ 1473K, strain rate 10-3s-1 to 10-1s-1 show that the mechanical behavior of 90W alloy is affected by the coupling of temperature and strain rate. At 1473K, the mechanical properties of 90W alloy deteriorate obviously at the strain rate 10-3s-1. The abnormal growth of tungsten particles appears in the center of the sample. When compressed at 1073K, the edge corner of the specimen appears in a 45 擄shear band in the compression direction, and the temperature rises to 1473K, and the phase interface at the edge corner produces a large number of defects due to the inconsistency of deformation. In order to describe the plastic deformation behavior of 90W alloy at high temperature, six constitutive equations were established based on JC model, modified JC model, Arrhenius model and modified ZA model. The constitutive equations of JC and modified JC are established based on 293K and 1073K, respectively. The accuracy and predictability of each equation are calculated quantitatively by using correlation coefficient and average relative error. By comparison, it can be concluded that the constitutive equation based on Arrhenius model and modified ZA model has higher accuracy and fitting degree, and the error of constitutive equation established by JC model and modified JC model is large. This is because the Arrhenius model and the ZA model take into account the coupling effect of temperature, strain and strain rate on the stress.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG146.411
，
本文編號：2346915
[Abstract]:High density tungsten alloy is a typical two-phase alloy with excellent properties such as high density, high strength and good plasticity. The armor-piercing projectile is in the coupled environment of temperature field and stress-strain field during the process of launching, flying and penetrating through the armour. Therefore, it is necessary to study the deformation and failure behavior of tungsten alloy under the temperature field and stress-strain field. In this paper, 90W-7Ni-3Fe high density tungsten alloy sintered in liquid phase was selected as the experimental material. The tensile and compression mechanical properties of tungsten alloy at different strain rates at room temperature and high temperature were studied. The dynamic mechanical properties and microstructure of tungsten alloy at room temperature were also analyzed experimentally, and constitutive equations based on different models were established. The basic physical and mechanical parameters of sintered 90W alloy were measured and characterized. The mechanical properties and microstructure of 90W alloy at room temperature were analyzed experimentally. It is found that the tensile strength of 90W alloy decreases with the increase of strain rate at room temperature, the cleavage fracture of W particles increases and the ductile tear of bonding phase decreases. At room temperature compression, plastic deformation is the process of coordination between tungsten phase and bonding phase deformation, and the plasticity is the highest at strain rate 10-3s-1. Under dynamic compression, the yield strength of 90W alloy is obviously higher than that of quasi-static compression. The tensile test results at 473-1473K show that the strain rate has no significant effect on the mechanical properties at high temperature. It was found that the strength and plasticity of 90W alloy changed obviously at 673K and 1273K, the strength decreased obviously at 473-673K, and then increased and stable steps appeared until 1273K. The plasticity is the highest at 673K, and decreases slowly at 1273K with the increase of temperature. By scanning the fracture surface, it is found that at 673K, the fracture mode of 90W is mainly the ductile tear of the bonding phase, and the W-W intergranular fracture is rarely seen. The compression tests of 90W alloy at 1073 ~ 1473K, strain rate 10-3s-1 to 10-1s-1 show that the mechanical behavior of 90W alloy is affected by the coupling of temperature and strain rate. At 1473K, the mechanical properties of 90W alloy deteriorate obviously at the strain rate 10-3s-1. The abnormal growth of tungsten particles appears in the center of the sample. When compressed at 1073K, the edge corner of the specimen appears in a 45 擄shear band in the compression direction, and the temperature rises to 1473K, and the phase interface at the edge corner produces a large number of defects due to the inconsistency of deformation. In order to describe the plastic deformation behavior of 90W alloy at high temperature, six constitutive equations were established based on JC model, modified JC model, Arrhenius model and modified ZA model. The constitutive equations of JC and modified JC are established based on 293K and 1073K, respectively. The accuracy and predictability of each equation are calculated quantitatively by using correlation coefficient and average relative error. By comparison, it can be concluded that the constitutive equation based on Arrhenius model and modified ZA model has higher accuracy and fitting degree, and the error of constitutive equation established by JC model and modified JC model is large. This is because the Arrhenius model and the ZA model take into account the coupling effect of temperature, strain and strain rate on the stress.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TG146.411
，
本文編號：2346915
本文鏈接：http://sikaile.net/kejilunwen/jiagonggongyi/2346915.html
最近更新
教材專著
