上海交通大学：《Design & Manufacturing II and Project》课程教学资源（讲义）Lecture 2 Material Selection

ME350 Mechanical Design and Manufacturing II ME350- Material Selection 1

ME 350 1 ME 350 Mechanical Design and Manufacturing II Material Selection

Materials What type of materials are there? What material characteristics are important in a design? 2

ME 350 2 Materials What type of materials are there? What material characteristics are important in a design?

ME350= Materials Characteristics: 1.Metals Density 2.Polymers Stiffness 3.Ceramics Strength....... 3

ME 350 3 Materials : Characteristics: 1. Metals Density 2. Polymers Stiffness 3. Ceramics Strength ……

ME350- 玻途T从 涂从 4

ME 350 4

ME350- cup liner ball handle 5

ME 350 5 cup liner ball handle

Metals 104 Polymers Ceramics Lead Density? Copper Steels Cast iron Density may be viewed as Zinc alloys the mass per unit volume. Sintered iron It governs how much the part will weigh. Alumina Aluminum tin Silicon nitride Silicon carbide Aluminum Magnesium Silicone rubber Graphite Figure 3.11 Acetal Density for various Phenol formal- dehyde metals,polymers, Nylon and ceramics at room temperature 103 Natural rubber Polyethylene (20^C;68f.[From ESDU Data Item No.84041 8×102 (1984]

ME 350 6 Density2 Density may be viewed as the mass per unit volume. It governs how much the part will weigh

Density,p Material kg/m3 Ibm/in.3 Metals Density Aluminum and its alloys" 2.7×103 0.097 Aluminum tin 3.1×103 .11 Babbitt,lead-based white metal 10.1×103 .36 Babbitt,tin-based white metal 7.4×103 27 Brasses 8.6×103 Bronze,aluminum 7.5×103 引 Bronze,leaded 8.9×103 32 Bronze,phosphor(cast)b 8.7×103 Bronze,porous 6.4×103 Copper 8.9×103 Copper lead 9.5×10 Iron,cast 7.4×103 132472 Iron,porous 6.1×103 Iron,wrought 7.8×103 8 Magnesium alloys 1.8×103 .065 Steels 7.8×103 .28 Zinc alloys 6.7×103 .24 Polymers Acetal(polyformaldehyde) 1.4×103 051 Nylons(polyamides) 1.14×103 .041 Polyethylene,high density .95×103 034 Phenol formaldehyde 1.3×103 .047 Rubber,naturald 1.0×103 .036 Rubber,silicone 1.8×103 .065 Ceramics Alumina(Al2O3) 3.9×103 .14 Graphite,high strength 1.7×103 .061 Silicon carbide(SiC) 2.9×103 .10 Silicon nitride(SigN) 3.2×103 .12 Structural alloys. Bar stock,typically 8.8x 103 kg/m3 (0.03 Ibm/in.3). Excluding "refractory"steels. d"Mechanical"rubber

ME 350 7 Density Properties2

1012 Metals Polymers Ceramics Stiffness2 Carbides Alumina Steels Cast iron 10" Brass,bronze Aluminum Zinc alloys Magnesium alloys Babbitts Graphite .Stiffness can be viewed as the ability to resist 100 deformation. 品 Phenol formal- dehyde Acetal Nylon .The commonly related 109 Polyethylene material measure is Modulus sninpow of Elasticity. 108 107 Natural rubber 106 Figure 3.12 Modulus of elasticity for various metals,polymers,and ceramics at room temperature(20'C;68'F).[From ESDU Data Item No. 84041(1984.月

ME 350 8 Stiffness2 •Stiffness can be viewed as the ability to resist deformation. •The commonly related material measure is Modulus of Elasticity

Modulus of Elasticity and Poisson's s ratio Prop Table 3.2 Modulus of elasticity for various metals, Table 3.3 Poisson's ratio for various metals polymers,and ceramics at room temperature (20'C;68"F).[From ESDU Data ltem No. polymers,and ceramics at room 84041(19841月 temperature (20'C;68"F).[From ESDU Data Item No.84041 Modulus of elasticity,E (19841] Material GPa Mpsi Metals Aluminum 62 9.0 Material Poisson's ratio,v Aluminum alloys" 0 10.2 Aluminum tin 63 Metals Babbitt,lead-based white metal Babbitt,tin-based white metal 器 Aluminum and its alloys" 033 Brasses 100 Aluminum tin Bronze,aluminum 117 17.0 Babbitt,lead-based white metal Bronze,leaded 密 Babbitt,tin-based white metal Bronze,phosphor Brasses 3 Bronze.porous 0 Copper 124 18.0 Bronze 3 Iron,gray cast 109 Bronze,porous 22 Iron,malleable cast 170 3 Iron,spheroidal graphite 15 23.1 Copper Iron,porous 0 11.6 Copper lead Iron,wrought 1 24.7 Iron,cast Magnesium alloys 41 5.9 Iron,porous Steel,low alloys 1 28.4 Steel,medium and high alloys 200 29.0 Iron,wrought 30 Steel,stainless 193 28.0 Magnesium alloys Steel,high speed 212 30.7 Steels 30 Zinc alloys 0 7.3 Polymers Zinc alloys 27 Acetal(polyformaldehyde) 2.7 .39 Polymers Nylons(polyamides) 1.9 .28 Acetal(polyformaldehyde) Polyethylene,high density 9 3 Phenol formaldehyde* Nylons(polyamides) .40 7.0 1.02 Rubber,natural' .004 .0006 Polyethylene,high density 35 Ceramics Phenol formaldehyde Alumina(Al2O3) 390 56.6 Rubber .50 Graphite 7 3.9 Cemented carbides 450 65.3 Ceramics Silicon carbide(SiC) 450 65.3 Alumina(Al2O3) .28 Silicon nitride (SigN) 314 45.5 Graphite,high strength Cemented carbides .19 Structural alloys. Silicon carbide(SiC) 19 bFor bearings. Silicon nitride(SigN4) 26 Precipitation-hardened alloys up to 211 GPa(30 Mpsi]. dSome alloys up to 96 GPa (14 Mpsi). Structural alloys

ME 350 9 Modulus of Elasticity and Poisson’s ratio Properties 2

Strength,Toughness,Hardness, Resilience2,3 ME350- ·Strength >Ability to resist yielding/breaking. Common measures are the Yield Stress or Ultimate Stress. ·Toughness >Ability to withstand impact or resist breaking. Common measure is the energy or work necessary to fracture the material. ·Hardness >Ability to resist abrasion/scratching. Common measures are the Brinell or Rockwell Hardness Test. 10

ME 350 10 Strength, Toughness, Hardness, Resilience 2,3 • Strength ØAbility to resist yielding/breaking. ØCommon measures are the Yield Stress or Ultimate Stress. • Toughness ØAbility to withstand impact or resist breaking. ØCommon measure is the energy or work necessary to fracture the material. • Hardness ØAbility to resist abrasion/scratching. ØCommon measures are the Brinell or Rockwell Hardness Test