STEM Career Outlook

Wages, employment opportunities, and growth projections for STEM jobs.

Mechanical Engineers Outlook

Guide for those interested in becoming a mechanical engineer. Includes qualifications, pay, and job duties.

Essentials of Manufacturing

Information, coverage of important developments and expert commentary in manufacturing.

3D Scanners

A white paper to assist in the evaluation of 3D scanning hardware solutions.

more free publications

The critical stress intensity factors Kc for some engineering materials are grouped in the following categories.

Toughness of Metals
Material Kc
(MPa·m1/2)
Yield Strength
(MPa)
Aluminum Alloy    
  2014 18-31 380-470
  2020 19-27 525-240
  2024 21-37 305-455
  2124 21-36 440-460
  2219 28-41 340-345
  7049 21-38 460-510
  7050 25-41 430-510
  7075 16-41 395-560
  7475 33-44 395-515
  7079 24-33 505-540
  7178 17-30 470-540
Ferrous Alloy    
  Cast Iron 6-20 120-290
  Roter Steel (A533) 204-214 -
  Pressure-vessel Steel (HY130) 170 -
  High-Strength Steel 50-154 -
  Mild Steel 140 -
  Medium-Carbon Steel 51 -
  4330V 86-110 1315-1400
  4340 44-91 1360-1660
  D6AC 62-102 1495-1570
  9-4-20 132-154 1280-1310
  18Ni 50-110 1450-1905
  AFC77 79 1530
Titanium Alloy    
  Ti6Al4V 77-116 815-875
Other Metals    
  Beryllium (Be) 4
Toughness of Polymers
Material Kc
(MPa·m1/2)
ABS 4
Epoxy 0.3-0.5
Nylon 3
Polycarbonate 1-2.6
Polyester 0.5
Polyethylene 1-2
Polypropylene 3
Polystyrene 2
PMMA 0.5-1.75
Toughness of Ceramics
Material Kc
(MPa·m1/2)
Electric Porcelain 1
Soda Glass 0.7-0.8
Alumina (Al2O3) 3-5
Toughness of Composites
Material Kc
(MPa·m1/2)
GFRP 20-60
CFRP 23-45
Boron Fiber-Epoxy 46
Wood (along grain) 0.5-1
Toughness of Minerals
Material Kc
(MPa·m1/2)
Shale 0.6
Soda Glass 0.7-0.8
Cement/Concrete 0.2
Granite 3
Toughness of Synthetic Materials
Material Kc
(MPa·m1/2)
Cement/Concrete 0.2
Cement/Concrete, Steel Reinforced 10-15
Silicon Nitride (Si3N4) 4-5
Cobalt Carbite 14-16
Silicon Carbite (SiC) 3
Tungsten Carbite 14-16
Magnesia (MgO) 3
Alumina (Al2O3) 3-5
Glossary
STEM Career Outlook

Wages, employment opportunities, and growth projections for STEM jobs.

Mechanical Engineers Outlook

Guide for those interested in becoming a mechanical engineer. Includes qualifications, pay, and job duties.

Essentials of Manufacturing

Information, coverage of important developments and expert commentary in manufacturing.

3D Scanners

A white paper to assist in the evaluation of 3D scanning hardware solutions.