Solution:

1. There are some materials that are commonly used in connecting rods such as alloys of steel, aluminum and titanium. Mostly connecting rods are made by forged steel. It is widely use because it has high tensile and compressive strength.

2. Titanium is used in making connecting rods, since very long time but when it comes to lightweight of connecting rod, aluminum is preferred. Titanium is the most costly material among steel and aluminum. Another demerit of titanium is their fatigue life. Aluminum is also used for a long time.

3. Most of the connecting rods are made of steel but aluminum can also be used to manufacture connecting rods because of its light weight and it can also absorb high impact shock but its durability will be suffered. Titanium can also be used because it has good strength but it is expensive.

4. When the carbon steel material of connecting rod is replaced with aluminum 360 it has been found that the weight of aluminum 360 connecting rod is 4 times lighter than carbon steel. It is because density of Al360 is very less compared to carbon steel